chore: update changelog

CHANGELOG.md

@@ -20,6 +20,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
     * Automatically support HEAD requests for all GET requests
     * Event loop uses `epoll` instead of `poll`
     * Configurable multithreading using `epoll`
+* LSM
+    * Binary tree iterators
+    * Trie iterators
+    * Store iterators
+* LTM - Lander Template Library
+    * Simple string templates
+    * Fully streamable template instances
+* Lander
+    * Simple paste pages with syntax highlighting
+    * Index pages that group elements under the same namespace into an overview
 * Landerctl
     * `-c` flag to use custom config file (useful for testing)
 

Makefile

@@ -42,7 +42,11 @@ liblsm:
 liblnm:
 	$(MAKE) -C lnm
 
-$(BIN): liblsm liblnm $(OBJS)
+.PHONY: libltm
+libltm:
+	$(MAKE) -C ltm
+
+$(BIN): liblsm liblnm libltm $(OBJS)
 	$(CC) -o $@ $(OBJS) $(_LDFLAGS)
 
 $(BUILD_DIR)/$(SRC_DIR)/%.c.o: $(SRC_DIR)/%.c
@@ -67,7 +71,7 @@ run: $(BIN)
 valgrind: $(BIN)
 	LANDER_API_KEY=test \
 		LANDER_DATA_DIR=data \
-		valgrind --track-origins=yes '$(BUILD_DIR)/$(BIN_FILENAME)'
+		valgrind --track-origins=yes --leak-check=full '$(BUILD_DIR)/$(BIN_FILENAME)'
 
 .PHONY: test
 test: $(TARGETS_TEST)

config.mk

@@ -7,16 +7,16 @@ SRC_DIR        = src
 TEST_DIR       = test
 THIRDPARTY_DIR = thirdparty
 
-INC_DIRS  = include $(THIRDPARTY_DIR)/include lsm/include lnm/include
+INC_DIRS  = include $(THIRDPARTY_DIR)/include lsm/include lnm/include ltm/include
-LIBS      = lsm lnm
+LIBS      = lsm lnm ltm
-LIB_DIRS  = ./lsm/build ./lnm/build
+LIB_DIRS  = ./lsm/build ./lnm/build ./ltm/build
 
 # -MMD: generate a .d file for every source file. This file can be imported by
 #  make and makes make aware that a header file has been changed, ensuring an
 #  object file is also recompiled if only a header is changed.
 # -MP: generate a dummy target for every header file (according to the  docs it
 #  prevents some errors when removing header files)
-CFLAGS ?= -MMD -MP -g
+CFLAGS ?= -MMD -MP -g -Wall
 
 # When compiling release builds, these flags are better
 # CLAGS = -O3

include/lander.h

@@ -4,16 +4,22 @@
 #include "lnm/common.h"
 #include "lnm/http/loop.h"
 #include "lsm/store.h"
+#include "ltm/template.h"
 
 extern const char lander_key_charset[];
 
 typedef struct lander_gctx {
   const char *data_dir;
   lsm_store *store;
+  struct {
+    ltm_template *paste;
+    ltm_template *index;
+  } templates;
 } lander_gctx;
 
 typedef struct lander_ctx {
   lsm_entry_handle *entry;
+  ltm_instance *instance;
 } lander_ctx;
 
 typedef enum lander_attr_type : uint8_t {
@@ -27,6 +33,7 @@ typedef enum lander_entry_type : uint8_t {
   lander_entry_type_redirect = 0,
   lander_entry_type_paste = 1,
   lander_entry_type_file = 2,
+  lander_entry_type_index = 3,
 } lander_entry_type;
 
 void *lander_gctx_init();
@@ -37,7 +44,7 @@ void lander_ctx_reset(lander_ctx *ctx);
 
 void lander_ctx_free(lander_ctx *ctx);
 
-lnm_http_step_err lander_get_index(lnm_http_conn *conn);
+lnm_http_step_err lander_get_root(lnm_http_conn *conn);
 
 lnm_http_step_err lander_get_entry(lnm_http_conn *conn);
 
@@ -53,6 +60,8 @@ lnm_http_step_err lander_remove_entry(lnm_http_conn *conn);
 
 lnm_http_step_err lander_post_file(lnm_http_conn *conn);
 
+lnm_http_step_err lander_post_index(lnm_http_conn *conn);
+
 /**
  * Store the requested header as an attribute, if it's present.
  */

lsm/include/lsm.h

@@ -27,6 +27,7 @@ typedef enum lsm_error {
   lsm_error_null_value = 4,
   lsm_error_failed_io = 5,
   lsm_error_lock_busy = 6,
+  lsm_error_done = 7,
 } lsm_error;
 
 /*typedef struct lsm_string { */

lsm/include/lsm/bt.h

@@ -1,6 +1,8 @@
 #ifndef LSM_BT
 #define LSM_BT
 
+#include <stdbool.h>
+
 #include "lsm.h"
 
 /**
@@ -8,6 +10,11 @@
  */
 typedef struct lsm_bt lsm_bt;
 
+/**
+ * A node inside an `lsm_bt` binary tree.
+ */
+typedef struct lsm_bt_node lsm_bt_node;
+
 /**
  * Initialize a new binary tree
  *
@@ -68,4 +75,33 @@ lsm_error lsm_bt_remove(void **out, lsm_bt *bt, char key);
  */
 lsm_error lsm_bt_replace(void **out, lsm_bt *bt, char key, void *data);
 
+/**
+ * Struct representing an in-flight iterator over the binary tree
+ */
+typedef struct lsm_bt_iterator {
+  lsm_bt_node *next;
+} lsm_bt_iterator;
+
+/**
+ * Initialize the given iterator for the binary tree.
+ *
+ * The iterator is explicitely allowed to be allocated by the user, as these are
+ * commonly used inside functions where they can simply be stored on the stack.
+ *
+ * @param out iterator to initialize
+ * @param bt binary tree to iterate
+ */
+void lsm_bt_iter(lsm_bt_iterator *out, const lsm_bt *bt);
+
+/**
+ * Advance the iterator to the next element.
+ *
+ * @param out where to store pointer to data; ignored if NULL
+ * @param key_out where to store key; ignored if NULL
+ * @param iter iterator to advance
+ * @return true if a new entry was returned, false if the iterator has no more
+ * entries to return
+ */
+bool lsm_bt_iter_next(void **out, char *key_out, lsm_bt_iterator *iter);
+
 #endif

lsm/include/lsm/store.h

@@ -98,6 +98,11 @@ lsm_error lsm_entry_attr_insert_uint8_t(lsm_entry_handle *handle, uint8_t type,
 lsm_error lsm_entry_attr_remove(lsm_str **out, lsm_entry_handle *handle,
                                 uint8_t type);
 
+/**
+ * Retrieve a pointer to the entry's key.
+ */
+void lsm_entry_key(const lsm_str **out, lsm_entry_handle *handle);
+
 /**
  * A store consisting of LSM entries.
  *
@@ -228,4 +233,40 @@ lsm_error lsm_entry_data_read(uint64_t *out, char *buf,
  */
 uint64_t lsm_entry_data_len(lsm_entry_handle *handle);
 
+/**
+ * Represents an in-flight iterator over an LSM store.
+ */
+typedef struct lsm_store_iterator lsm_store_iterator;
+
+/**
+ * Initialize an iterator to iterate over all entries with keys starting
+ * with the given prefix.
+ *
+ * @param out pointer to store iterator pointer in
+ * @param trie trie to iterate
+ * @param prefix prefix of the keys; a zero-length string means iterating over
+ *  the entire trie; NULL is interpreted as a zero-length string
+ */
+lsm_error lsm_store_iter(lsm_store_iterator **out, lsm_store *store,
+                         const lsm_str *prefix);
+
+/**
+ * Advance the iterator, returning a read handle to the next entry. The caller
+ * is responsible for closing this handle.
+ */
+lsm_error lsm_store_iter_next_read(lsm_entry_handle **out,
+                                   lsm_store_iterator *iter);
+
+/**
+ * Advance the iterator, returning a write handle to the next entry. The caller
+ * is responsible for closing this handle.
+ */
+/* lsm_error lsm_store_iter_next_write(lsm_entry_handle **out,
+ * lsm_store_iterator *iter); */
+
+/**
+ * Free the given iterator.
+ */
+void lsm_store_iter_free(lsm_store_iterator *iter);
+
 #endif

lsm/include/lsm/str.h

@@ -178,6 +178,15 @@ lsm_error lsm_str_split(lsm_str *s, lsm_str *s2, uint64_t index);
  * @param s string to append s2 to
  * @param s2 string to append to s
  */
-lsm_error lsm_str_append(lsm_str *s, lsm_str *s2);
+lsm_error lsm_str_append(lsm_str *s, const lsm_str *s2);
+
+/**
+ * Same as `lsm_str_append`, but it takes a C-style string instead.
+ *
+ * @param s string to append c_str to
+ * @param c_str char buffer to append
+ * @param len length of c_str
+ */
+lsm_error lsm_str_append_c(lsm_str *s, const char *c_str, uint64_t len);
 
 #endif

lsm/include/lsm/trie.h

@@ -1,7 +1,10 @@
 #ifndef LSM_TRIE
 #define LSM_TRIE
 
+#include <stdlib.h>
+
 #include "lsm.h"
+#include "lsm/bt.h"
 #include "lsm/str.h"
 
 /**
@@ -9,6 +12,11 @@
  */
 typedef struct lsm_trie lsm_trie;
 
+/**
+ * A node inside an `lsm_trie` trie
+ */
+typedef struct lsm_trie_node lsm_trie_node;
+
 /**
  * Initialize a new trie.
  *
@@ -57,4 +65,36 @@ lsm_error lsm_trie_remove(void **out, lsm_trie *trie, const lsm_str *key);
  */
 uint64_t lsm_trie_size(const lsm_trie *trie);
 
+/**
+ * Represents an in-flight iterator over a trie
+ */
+typedef struct lsm_trie_iterator lsm_trie_iterator;
+
+/**
+ * Initialize an iterator to iterate over all entries with keys starting
+ * with the given prefix.
+ *
+ * @param out pointer to store iterator pointer in
+ * @param trie trie to iterate
+ * @param prefix prefix of the keys; a zero-length string means iterating over
+ *  the entire trie; NULL is interpreted as a zero-length string
+ */
+lsm_error lsm_trie_iter(lsm_trie_iterator **out, const lsm_trie *trie,
+                        const lsm_str *prefix);
+
+/**
+ * Advance the given iterator.
+ *
+ * @param out pointer to store next data pointer in
+ * @param iter iterator to advance
+ * @return `lsm_error_ok` if next element has been returned, `lsm_error_done` if
+ *  no more elements are present, or some other error code
+ */
+lsm_error lsm_trie_iter_next(void **out, lsm_trie_iterator *iter);
+
+/**
+ * Free the given iterator.
+ */
+void lsm_trie_iter_free(lsm_trie_iterator *iter);
+
 #endif

lsm/src/_include/lsm/bt_internal.h

@@ -9,12 +9,13 @@
 /**
  * Node inside a binary tree
  */
-typedef struct lsm_bt_node {
+struct lsm_bt_node {
   struct lsm_bt_node *left;
   struct lsm_bt_node *right;
+  struct lsm_bt_node *parent;
   void *data;
   char key;
-} lsm_bt_node;
+};
 
 /**
  * Initialize a new binary tree node

lsm/src/_include/lsm/store_internal.h

@@ -34,6 +34,11 @@ typedef struct lsm_entry {
   uint64_t idx_file_offset;
 } lsm_entry;
 
+struct lsm_store_iterator {
+  lsm_trie_iterator *iter;
+  lsm_store *store;
+};
+
 /**
  * Allocate and initialize a new lsm_entry object.
  *

lsm/src/_include/lsm/trie_internal.h

@@ -5,14 +5,11 @@
 #include "lsm/str_internal.h"
 #include "lsm/trie.h"
 
-/**
+struct lsm_trie_node {
- * A node inside a trie structure
- */
-typedef struct lsm_trie_node {
   lsm_bt bt;
   lsm_str skip;
   void *data;
-} lsm_trie_node;
+};
 
 /**
  * Allocate and initialize a new trie node
@@ -33,4 +30,13 @@ struct lsm_trie {
   uint64_t size;
 };
 
+struct lsm_trie_iterator {
+  lsm_trie_node *next;
+  struct {
+    lsm_bt_iterator *arr;
+    size_t len;
+    size_t cap;
+  } stack;
+};
+
 #endif

lsm/src/bt/lsm_bt.c

@@ -1,5 +1,6 @@
 #include <stdlib.h>
 
+#include "lsm/bt.h"
 #include "lsm/bt_internal.h"
 
 lsm_error lsm_bt_node_init(lsm_bt_node **ptr, const char key, void *data) {
@@ -60,10 +61,12 @@ void lsm_bt_free(lsm_bt *bt) {
 uint64_t lsm_bt_size(const lsm_bt *bt) { return bt->size; }
 
 lsm_error lsm_bt_insert(lsm_bt *bt, char key, void *data) {
+  lsm_bt_node *parent = NULL;
   lsm_bt_node **dest = &bt->root;
 
   // Traverse down the tree until we reach the new point to insert our node
   while ((*dest != NULL) && ((*dest)->key != key)) {
+    parent = *dest;
     dest = key < (*dest)->key ? &(*dest)->left : &(*dest)->right;
   }
 
@@ -71,9 +74,8 @@ lsm_error lsm_bt_insert(lsm_bt *bt, char key, void *data) {
     return lsm_error_already_present;
   }
 
-  if (lsm_bt_node_init(dest, key, data) != lsm_error_ok) {
+  LSM_RES(lsm_bt_node_init(dest, key, data));
-    return lsm_error_failed_alloc;
+  (*dest)->parent = parent;
-  }
 
   bt->size++;
 
@@ -125,13 +127,27 @@ lsm_error lsm_bt_remove(void **out, lsm_bt *bt, char key) {
     (*dest)->data = (*succ)->data;
 
     lsm_bt_node *succ_replacement = (*succ)->right;
+    lsm_bt_node *parent = (*succ)->parent;
+
     lsm_bt_node_free(*succ);
+
     *succ = succ_replacement;
+
+    if (*succ != NULL) {
+      (*succ)->parent = parent;
+    }
   } else {
     lsm_bt_node *replacement =
         (*dest)->left != NULL ? (*dest)->left : (*dest)->right;
+    lsm_bt_node *parent = (*dest)->parent;
+
     lsm_bt_node_free(*dest);
+
     *dest = replacement;
+
+    if (*dest != NULL) {
+      (*dest)->parent = parent;
+    }
   }
 
   return lsm_error_ok;
@@ -156,3 +172,45 @@ lsm_error lsm_bt_replace(void **out, lsm_bt *bt, char key, void *data) {
 
   return lsm_error_ok;
 }
+
+void lsm_bt_iter(lsm_bt_iterator *out, const lsm_bt *bt) {
+  out->next = bt->root;
+
+  if (bt->root != NULL) {
+    // Initialize the iterator to the smallest element in the tree
+    while (out->next->left != NULL) {
+      out->next = out->next->left;
+    }
+  }
+}
+
+bool lsm_bt_iter_next(void **out, char *key_out, lsm_bt_iterator *iter) {
+  if (iter->next == NULL) {
+    return false;
+  }
+
+  if (out != NULL) {
+    *out = iter->next->data;
+  }
+
+  if (key_out != NULL) {
+    *key_out = iter->next->key;
+  }
+
+  if (iter->next->right != NULL) {
+    iter->next = iter->next->right;
+
+    while (iter->next->left != NULL) {
+      iter->next = iter->next->left;
+    }
+  } else {
+    while ((iter->next->parent != NULL) &&
+           (iter->next->parent->right == iter->next)) {
+      iter->next = iter->next->parent;
+    }
+
+    iter->next = iter->next->parent;
+  }
+
+  return true;
+}

lsm/src/store/lsm_store_entry.c

@@ -316,3 +316,7 @@ lsm_error lsm_entry_data_open_read(lsm_entry_handle *handle) {
 
   return lsm_error_ok;
 }
+
+void lsm_entry_key(const lsm_str **out, lsm_entry_handle *handle) {
+  *out = handle->wrapper->entry->key;
+}

lsm/src/store/lsm_store_iter.c

@@ -0,0 +1,58 @@
+#include "lsm/store.h"
+#include "lsm/store_internal.h"
+
+lsm_error lsm_store_iter(lsm_store_iterator **out, lsm_store *store,
+                         const lsm_str *prefix) {
+  lsm_trie_iterator *trie_iter;
+  LSM_RES(lsm_trie_iter(&trie_iter, store->trie, prefix));
+
+  lsm_store_iterator *iter = calloc(1, sizeof(lsm_store_iterator));
+
+  if (iter == NULL) {
+    lsm_trie_iter_free(trie_iter);
+
+    return lsm_error_failed_alloc;
+  }
+
+  iter->iter = trie_iter;
+  iter->store = store;
+
+  *out = iter;
+
+  return lsm_error_ok;
+}
+
+lsm_error lsm_store_iter_next_read(lsm_entry_handle **out,
+                                   lsm_store_iterator *iter) {
+  lsm_entry_wrapper *wrapper = NULL;
+
+  // Traverse through the trie until a node is found with a filled data field
+  do {
+    // Exits function if iterator is done
+    LSM_RES(lsm_trie_iter_next((void **)&wrapper, iter->iter));
+
+    // TODO error handling?
+    pthread_rwlock_rdlock(&wrapper->lock);
+
+    if (wrapper->entry == NULL) {
+      pthread_rwlock_unlock(&wrapper->lock);
+
+      wrapper = NULL;
+    }
+  } while (wrapper == NULL);
+
+  lsm_entry_handle *handle;
+  LSM_RES2(lsm_entry_handle_init(&handle),
+           pthread_rwlock_unlock(&wrapper->lock));
+
+  handle->wrapper = wrapper;
+  handle->store = iter->store;
+  *out = handle;
+
+  return lsm_error_ok;
+}
+
+void lsm_store_iter_free(lsm_store_iterator *iter) {
+  lsm_trie_iter_free(iter->iter);
+  free(iter);
+}

lsm/src/str/lsm_str.c

@@ -215,15 +215,15 @@ bool lsm_str_eq(const lsm_str *s1, const lsm_str *s2) {
   return memcmp(lsm_str_ptr(s1), lsm_str_ptr(s2), s1->len) == 0;
 }
 
-lsm_error lsm_str_append(lsm_str *s, lsm_str *s2) {
+lsm_error lsm_str_append_c(lsm_str *s, const char *c_str, uint64_t len) {
-  if (s2->len == 0) {
+  if (len == 0) {
     return lsm_error_ok;
   }
 
-  uint64_t new_len = s->len + s2->len;
+  uint64_t new_len = s->len + len;
 
   if (new_len <= 8) {
-    memcpy(&s->data.val[s->len], s2->data.val, s2->len);
+    memcpy(&s->data.val[s->len], c_str, len);
   } else {
     char *buf;
 
@@ -243,11 +243,15 @@ lsm_error lsm_str_append(lsm_str *s, lsm_str *s2) {
       }
     }
 
-    memcpy(&buf[s->len], lsm_str_ptr(s2), s2->len);
+    memcpy(&buf[s->len], c_str, len);
     s->data.ptr = buf;
   }
 
-  s->len += s2->len;
+  s->len += len;
 
   return lsm_error_ok;
 }
+
+lsm_error lsm_str_append(lsm_str *s, const lsm_str *s2) {
+  return lsm_str_append_c(s, lsm_str_ptr(s2), s2->len);
+}

lsm/src/trie/lsm_trie_iter.c

@@ -0,0 +1,117 @@
+#include "lsm.h"
+#include "lsm/trie_internal.h"
+
+/**
+ * Advance the iterator so that `next` now points to a node containing data. If
+ * no more data nodes are found, `next` is set to NULL. The initial value of
+ * `next` is ignored.
+ */
+lsm_error lsm_trie_iter_next_data_node(lsm_trie_iterator *iter) {
+  do {
+    // Traverse back up the stack until we reach either the end of the subtree,
+    // or an iterator that hasn't been exhausted yet
+    while ((iter->stack.len > 0) &&
+           !lsm_bt_iter_next((void **)&iter->next, NULL,
+                             &iter->stack.arr[iter->stack.len - 1])) {
+      iter->stack.len--;
+    }
+
+    if (iter->stack.len == 0) {
+      iter->next = NULL;
+
+      return lsm_error_ok;
+    }
+
+    // Add node's subtree to the stack
+    if (iter->stack.len == iter->stack.cap) {
+      lsm_bt_iterator *arr = realloc(
+          iter->stack.arr, iter->stack.cap * 2 * sizeof(lsm_bt_iterator));
+
+      if (arr == NULL) {
+        return lsm_error_failed_alloc;
+      }
+
+      iter->stack.arr = arr;
+      iter->stack.cap *= 2;
+    }
+
+    lsm_bt_iter(&iter->stack.arr[iter->stack.len], &iter->next->bt);
+    iter->stack.len++;
+
+  } while (iter->next->data == NULL);
+
+  return lsm_error_ok;
+}
+
+lsm_error lsm_trie_iter(lsm_trie_iterator **out, const lsm_trie *trie,
+                        const lsm_str *prefix) {
+  uint64_t prefix_len = prefix == NULL ? 0 : lsm_str_len(prefix);
+
+  uint64_t index = 0;
+  lsm_trie_node *node = trie->root;
+
+  // Simplified traversal down the trie to find the root of the subtree
+  // contaiing all nodes with the given prefix
+  while ((index < prefix_len) && (node != NULL)) {
+    char c = lsm_str_char(prefix, index);
+    lsm_error res = lsm_bt_search((void **)&node, &node->bt, c);
+
+    switch (res) {
+    case lsm_error_ok:
+      index += 1 + lsm_str_len(&node->skip);
+      break;
+    case lsm_error_not_found:
+      node = NULL;
+      break;
+    default:
+      return res;
+    };
+  }
+
+  lsm_trie_iterator *iter = calloc(1, sizeof(lsm_trie_iterator));
+
+  if (iter == NULL) {
+    return lsm_error_failed_alloc;
+  }
+
+  iter->next = node;
+
+  if (node != NULL) {
+    lsm_bt_iterator *arr = malloc(sizeof(lsm_bt_iterator));
+
+    if (arr == NULL) {
+      free(iter);
+
+      return lsm_error_failed_alloc;
+    }
+
+    iter->stack.arr = arr;
+    iter->stack.cap = 1;
+    iter->stack.len = 1;
+
+    lsm_bt_iter(&iter->stack.arr[0], &node->bt);
+
+    if (node->data == NULL) {
+      LSM_RES(lsm_trie_iter_next_data_node(iter));
+    }
+  }
+
+  *out = iter;
+
+  return lsm_error_ok;
+}
+
+lsm_error lsm_trie_iter_next(void **out, lsm_trie_iterator *iter) {
+  if (iter->next == NULL) {
+    return lsm_error_done;
+  }
+
+  *out = iter->next->data;
+
+  return lsm_trie_iter_next_data_node(iter);
+}
+
+void lsm_trie_iter_free(lsm_trie_iterator *iter) {
+  free(iter->stack.arr);
+  free(iter);
+}

lsm/test/bt/bt.c

@@ -104,6 +104,33 @@ void test_remove_multiple() {
   lsm_bt_free(bt);
 }
 
+void test_iter() {
+  char chars[] = "falcoep";
+  size_t char_count = sizeof(chars) / sizeof(char) - 1;
+
+  char sorted_chars[] = "aceflop";
+
+  BT_INIT();
+
+  for (size_t i = 0; i < char_count; i++) {
+    TEST_CHECK(lsm_bt_insert(bt, chars[i], (void *)(i + 1)) == lsm_error_ok);
+  }
+
+  lsm_bt_iterator iter;
+  lsm_bt_iter(&iter, bt);
+
+  char key;
+  void *data;
+  size_t i = 0;
+
+  while (lsm_bt_iter_next(&data, &key, &iter)) {
+    TEST_CHECK_(key == sorted_chars[i], "%c == %c", key, sorted_chars[i]);
+    i++;
+  }
+
+  TEST_CHECK(i == char_count);
+}
+
 TEST_LIST = {
   { "bt init", test_init },
   { "bt insert first", test_insert_first },
@@ -111,5 +138,6 @@ TEST_LIST = {
   { "bt insert multiple", test_insert_multiple },
   { "bt remove root", test_remove_root },
   { "bt remove multiple", test_remove_multiple },
+  { "bt iter", test_iter },
   { NULL, NULL }
 };

lsm/test/trie/trie.c

@@ -25,8 +25,64 @@ void test_insert_one() {
   TEST_CHECK(data == (void *)1);
 }
 
+void test_iter() {
+  TRIE_INIT();
+
+  lsm_str *s;
+
+  lsm_str_init_copy(&s, "hello");
+  TEST_CHECK(lsm_trie_insert(trie, s, (void *)1) == lsm_error_ok);
+
+  lsm_str_init_copy(&s, "hella");
+  TEST_CHECK(lsm_trie_insert(trie, s, (void *)2) == lsm_error_ok);
+
+  lsm_str_init_copy(&s, "hel");
+  TEST_CHECK(lsm_trie_insert(trie, s, (void *)3) == lsm_error_ok);
+
+  lsm_str_init_copy(&s, "wow");
+  TEST_CHECK(lsm_trie_insert(trie, s, (void *)4) == lsm_error_ok);
+
+  lsm_str_init_copy(&s, "hel");
+
+  lsm_trie_iterator *iter;
+  TEST_CHECK(lsm_trie_iter(&iter, trie, s) == lsm_error_ok);
+
+  void *data;
+
+  TEST_CHECK(lsm_trie_iter_next(&data, iter) == lsm_error_ok);
+  TEST_CHECK_(data == (void *)3, "%p == %p", data, (void *)3);
+
+  TEST_CHECK(lsm_trie_iter_next(&data, iter) == lsm_error_ok);
+  TEST_CHECK_(data == (void *)2, "%p == %p", data, (void *)2);
+
+  TEST_CHECK(lsm_trie_iter_next(&data, iter) == lsm_error_ok);
+  TEST_CHECK_(data == (void *)1, "%p == %p", data, (void *)1);
+
+  TEST_CHECK(lsm_trie_iter_next(&data, iter) == lsm_error_done);
+  lsm_trie_iter_free(iter);
+
+  // Test full trie iterator
+  TEST_CHECK(lsm_trie_iter(&iter, trie, NULL) == lsm_error_ok);
+
+  TEST_CHECK(lsm_trie_iter_next(&data, iter) == lsm_error_ok);
+  TEST_CHECK_(data == (void *)3, "%p == %p", data, (void *)3);
+
+  TEST_CHECK(lsm_trie_iter_next(&data, iter) == lsm_error_ok);
+  TEST_CHECK_(data == (void *)2, "%p == %p", data, (void *)2);
+
+  TEST_CHECK(lsm_trie_iter_next(&data, iter) == lsm_error_ok);
+  TEST_CHECK_(data == (void *)1, "%p == %p", data, (void *)1);
+
+  TEST_CHECK(lsm_trie_iter_next(&data, iter) == lsm_error_ok);
+  TEST_CHECK_(data == (void *)4, "%p == %p", data, (void *)4);
+
+  TEST_CHECK(lsm_trie_iter_next(&data, iter) == lsm_error_done);
+  lsm_trie_iter_free(iter);
+}
+
 TEST_LIST = {
   { "trie init", test_init },
   { "trie insert one", test_insert_one },
+  { "trie iter", test_iter },
   { NULL, NULL }
 };

ltm/Makefile

@@ -0,0 +1,133 @@
+# https://spin.atomicobject.com/2016/08/26/makefile-c-projects/ was a great
+# base for this Makefile
+
+-include config.mk
+
+LIB := $(BUILD_DIR)/$(LIB_FILENAME)
+
+SRCS != find '$(SRC_DIR)' -iname '*.c'
+SRCS_H != find include -iname '*.h'
+SRCS_H_INTERNAL != find $(SRC_DIR) -iname '*.h'
+SRCS_TEST != find '$(TEST_DIR)' -iname '*.c'
+SRCS_EXAMPLE != find '$(EXAMPLE_DIR)' -iname '*.c'
+
+OBJS := $(SRCS:%=$(BUILD_DIR)/%.o)
+OBJS_TEST := $(SRCS_TEST:%=$(BUILD_DIR)/%.o)
+OBJS_EXAMPLE := $(SRCS_EXAMPLE:%=$(BUILD_DIR)/%.o)
+DEPS := $(SRCS:%=$(BUILD_DIR)/%.d) $(SRCS_TEST:%=$(BUILD_DIR)/%.d)
+
+BINS_TEST := $(OBJS_TEST:%.c.o=%)
+BINS_EXAMPLE := $(OBJS_EXAMPLE:%.c.o=%)
+
+TARGETS_TEST := $(BINS_TEST:%=test-%)
+TARGETS_MEM_TEST := $(BINS_TEST:%=test-mem-%)
+TARGETS_EXAMPLE := $(BINS_EXAMPLE:%=test-%)
+
+_CFLAGS := $(addprefix -I,$(INC_DIRS)) $(CFLAGS) -Wall -Wextra
+
+.PHONY: all
+all: lib
+
+
+# =====COMPILATION=====
+# Utility used by the CI to lint
+.PHONY: objs
+objs: $(OBJS)
+
+.PHONY: lib
+lib: $(LIB)
+$(LIB): $(OBJS)
+	ar -rcs $@ $(OBJS)
+
+$(BUILD_DIR)/$(SRC_DIR)/%.c.o: $(SRC_DIR)/%.c
+	mkdir -p $(dir $@)
+	$(CC) -c $(_CFLAGS) $< -o $@
+
+# =====TESTING=====
+.PHONY: test
+test: $(TARGETS_TEST)
+
+.PHONY: test-mem
+test-mem: $(TARGETS_MEM_TEST)
+
+.PHONY: $(TARGETS_TEST)
+$(TARGETS_TEST): test-%: %
+	./$^
+
+.PHONY: $(TARGETS_MEM_TEST)
+$(TARGETS_MEM_TEST): test-mem-%: %
+	valgrind --tool=memcheck --error-exitcode=1 --track-origins=yes --leak-check=full ./$^
+
+.PHONY: build-test
+build-test: $(BINS_TEST)
+
+$(BINS_TEST): %: %.c.o $(LIB)
+	$(CC) \
+		$^ -o $@
+
+# Along with the include directory, each test includes $(TEST_DIR) (which
+# contains the acutest.h header file), and the src directory of the module it's
+# testing. This allows tests to access internal methods, which aren't publicly
+# exposed.
+$(BUILD_DIR)/$(TEST_DIR)/%.c.o: $(TEST_DIR)/%.c
+	mkdir -p $(dir $@)
+	$(CC) $(_CFLAGS) -I$(TEST_DIR) \
+		-I$(dir $(@:$(BUILD_DIR)/$(TEST_DIR)/%=$(SRC_DIR)/%)) \
+		-c $< -o $@
+
+# =====EXAMPLES=====
+.PHONY: build-example
+build-example: $(BINS_EXAMPLE)
+
+$(BINS_EXAMPLE): %: %.c.o $(LIB)
+	$(CC) \
+		$^ -o $@
+
+# Example binaries link the resulting library
+$(BUILD_DIR)/$(EXAMPLE_DIR)/%.c.o: $(EXAMPLE_DIR)/%.c
+	mkdir -p $(dir $@)
+	$(CC) $(_CFLAGS) -I$(PUB_INC_DIR) -c $< -o $@
+
+# =====MAINTENANCE=====
+.PHONY: lint
+lint:
+	clang-format -n --Werror \
+		$(filter-out $(THIRDPARTY),$(SRCS)) \
+		$(filter-out $(THIRDPARTY),$(SRCS_H)) \
+		$(filter-out $(THIRDPARTY),$(SRCS_H_INTERNAL))
+
+.PHONY: fmt
+fmt:
+	clang-format -i \
+		$(filter-out $(THIRDPARTY),$(SRCS)) \
+		$(filter-out $(THIRDPARTY),$(SRCS_H)) \
+		$(filter-out $(THIRDPARTY),$(SRCS_H_INTERNAL))
+
+.PHONY: check
+check:
+	mkdir -p $(BUILD_DIR)/cppcheck
+	cppcheck \
+		$(addprefix -I,$(INC_DIRS)) \
+		--cppcheck-build-dir=$(BUILD_DIR)/cppcheck \
+		--error-exitcode=1 \
+		--enable=warning,style \
+		--inline-suppr \
+		--check-level=exhaustive \
+		--quiet \
+		-j$(shell nproc) \
+		$(filter-out $(THIRDPARTY),$(SRCS))
+
+.PHONY: clean
+clean:
+	rm -rf '$(BUILD_DIR)'
+
+
+.PHONY: bear
+bear: clean
+	bear -- make
+	bear --append -- make build-test
+	bear --append -- make build-example
+
+
+# Make make aware of the .d files
+-include $(DEPS)

ltm/README.md

@@ -0,0 +1,32 @@
+# LTM - Lander Template Module
+
+This module provides an interface for generating `char` streams from a given
+template.
+
+```html
+<body>
+    <h1>{{ title }}</h1>
+    <ul>
+{{ item start }}
+        <li><a href="{{ url }}">{{ name }}</a></li>
+{{ item end }}
+    </ul>
+</body>
+```
+
+The above snippet shows everything the templating language currently offers;
+either singular variables (here: `title`) or nested templates (here: `item`).
+Note the absence of a loop construct. This is because each variable and nested
+template is implicitely already a loop; a variable or a nested template can be
+added as many times as needed, and they will appear in the order they were
+added.
+
+Template strings are compiled into templates. From a template, an instance can
+be created to which the required data can be added to fill in the template.
+Instantiating a template does not modify the original template, meaning
+templates can be safely used concurrently.
+
+Each inserted variable can get its data from a variety of sources, namely
+`char` buffers, files or a custom reader function. The resulting `char` stream
+is never fully loaded into memory; an instance can stream its content to a
+provided buffer to prevent unnecessary memory usage.

ltm/config.mk

@@ -0,0 +1,17 @@
+LIB_FILENAME = libltm.a
+
+BUILD_DIR = build
+SRC_DIR = src
+TEST_DIR = test
+EXAMPLE_DIR = example
+THIRDPARTY = 
+
+PUB_INC_DIR = include
+INC_DIRS = $(PUB_INC_DIR) src/_include
+
+# -MMD: generate a .d file for every source file. This file can be imported by
+#  make and makes make aware that a header file has been changed, ensuring an
+#  object file is also recompiled if only a header is changed.
+# -MP: generate a dummy target for every header file (according to the  docs it
+#  prevents some errors when removing header files)
+CFLAGS ?= -MMD -MP -g -Wall -Werror

ltm/example/test.c

@@ -0,0 +1,48 @@
+#include <stdio.h>
+#include <sys/stat.h>
+
+#include "ltm/template.h"
+
+const char *s =  "<head><link rel=\"stylesheet\" href=\"https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/styles/default.min.css\">\n"
+  "<script src=\"https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/highlight.min.js\"></script>\n"
+  "<script>hljs.highlightAll();</script></head>\n"
+  "<body><pre><code>{{ paste }}</code></pre></body>";
+
+  ltm_err reader(size_t *written, char *buf, size_t len, void *data) {
+    FILE *f = data;
+
+    *written = fread(buf, 1, len, f);
+
+    return ltm_err_ok;
+  }
+
+int main() {
+  ltm_template *template;
+  ltm_template_compile(&template, s);
+  ltm_instance *instance;
+  ltm_template_instantiate(&instance, template);
+
+  const char *filename = "src/ltm_instance.c";
+
+  struct stat sb;
+  stat(filename, &sb);
+
+  FILE *f = fopen(filename, "rb");
+
+  ltm_instance_block_add_var_fn(instance, "paste", reader, f, sb.st_size);
+  /* ltm_instance_block_add_var(instance, "paste", ltm_instance_block_type_file_owned, f, sb.st_size); */
+  /* ltm_instance_block_add_var(instance, "paste", ltm_instance_block_type_buf, "hello\n", 6); */
+  /* ltm_instance_block_add_var(instance, "paste", ltm_instance_block_type_buf, "world\n", 6); */
+  
+  char buf[128];
+  size_t written = 0;
+
+  while (ltm_instance_write(&written, buf, 128, instance) != ltm_err_done) {
+    printf("%.*s", (int)written, buf);
+  }
+
+  printf("%.*s", (int)written, buf);
+
+  ltm_instance_free(instance);
+  ltm_template_free(template);
+}

ltm/include/ltm/common.h

@@ -0,0 +1,33 @@
+#ifndef LTM_COMMON
+#define LTM_COMMON
+
+#define LTM_RES(x)                                                             \
+  {                                                                            \
+    ltm_err res = x;                                                           \
+    if (res != ltm_err_ok)                                                     \
+      return res;                                                              \
+  }
+
+#define LTM_RES2(x, e)                                                         \
+  {                                                                            \
+    ltm_err res = x;                                                           \
+    if (res != ltm_err_ok) {                                                   \
+      e;                                                                       \
+      return res;                                                              \
+    }                                                                          \
+  }
+
+#define LTM_MIN(x, y) ((x) < (y) ? (x) : (y))
+#define LTM_MAX(x, y) ((x) > (y) ? (x) : (y))
+
+typedef enum ltm_err {
+  ltm_err_ok = 0,
+  ltm_err_invalid_template,
+  ltm_err_failed_alloc,
+  ltm_err_failed_io,
+  ltm_err_not_found,
+  ltm_err_wrong_block_type,
+  ltm_err_done,
+} ltm_err;
+
+#endif

ltm/include/ltm/template.h

@@ -0,0 +1,104 @@
+#ifndef LTM_TEMPLATE
+#define LTM_TEMPLATE
+
+#include <stdlib.h>
+
+#include "ltm/common.h"
+
+/**
+ * Represents a compiled template
+ */
+typedef struct ltm_template ltm_template;
+
+/**
+ * Compile the given template.
+ *
+ * @param out where to store pointer to newly allocated `ltm_template`
+ * @param template nul-terminated string containing the template
+ */
+ltm_err ltm_template_compile(ltm_template **out, const char *template);
+
+/**
+ * Compile the given template with a given length.
+ *
+ * @param out where to store pointer to newly allocated `ltm_template`
+ * @param template char buffer containing the template
+ * @param len length of the char buffer
+ */
+ltm_err ltm_template_compile_n(ltm_template **out, const char *template,
+                               size_t len);
+
+/**
+ * Free the template instance. After freeing a template, no instances associated
+ * with it are safe to use.
+ */
+void ltm_template_free(ltm_template *template);
+
+/**
+ * Represents a specific instance of a template.
+ */
+typedef struct ltm_instance ltm_instance;
+
+typedef ltm_err (*ltm_data_fn)(size_t *written, char *buf, size_t len,
+                               void *data);
+
+/**
+ * Create a new instance of the given template.
+ */
+ltm_err ltm_template_instantiate(ltm_instance **out,
+                                 const ltm_template *template);
+
+/**
+ * Free the given instance, as well as all nested instances.
+ */
+void ltm_instance_free(ltm_instance *instance);
+
+typedef enum ltm_instance_block_type {
+  ltm_instance_block_type_buf = 0,
+  ltm_instance_block_type_buf_owned,
+  ltm_instance_block_type_file,
+  ltm_instance_block_type_file_owned,
+  ltm_instance_block_type_nested,
+  ltm_instance_block_type_fn,
+} ltm_instance_block_type;
+
+/**
+ * Add a new variable to the template.
+ */
+ltm_err ltm_instance_block_add_var(ltm_instance *instance, const char *name,
+                                   ltm_instance_block_type type, void *data,
+                                   size_t len);
+
+/**
+ * Add a new variable to the template whose data is provided by a data function.
+ */
+ltm_err ltm_instance_block_add_var_fn(ltm_instance *instance, const char *name,
+                                      ltm_data_fn fn, void *data, size_t len);
+
+/**
+ * Add a new nested instance to the instance, returning a handle to the nested
+ * instance.
+ */
+ltm_err ltm_instance_block_add_nested(ltm_instance **out,
+                                      ltm_instance *instance, const char *name);
+
+/**
+ * Calculate the size of the resulting output of this instance.
+ */
+size_t ltm_instance_size(const ltm_instance *instance);
+
+/**
+ * Write at most `len` bytes to the given buffer.
+ *
+ * @param written outputs how many bytes were written to `buf`
+ * @param buf buffer to write to
+ * @param len length of the buffer
+ * @param instance instance to write
+ * @return `ltm_err_ok` if write was successful but there's more to be written,
+ * `ltm_err_done` if everything has been written successfully, or some other
+ * error code
+ */
+ltm_err ltm_instance_write(size_t *written, char *buf, size_t len,
+                           ltm_instance *instance);
+
+#endif

ltm/src/_include/ltm/template_internal.h

@@ -0,0 +1,119 @@
+#ifndef LTM_TEMPLATE_INTERNAL
+#define LTM_TEMPLATE_INTERNAL
+
+#include "ltm/template.h"
+
+typedef enum ltm_placeholder_type {
+  ltm_placeholder_type_invalid = 0,
+  ltm_placeholder_type_var,
+  ltm_placeholder_type_nested_start,
+  ltm_placeholder_type_nested_end,
+} ltm_placeholder_type;
+
+/**
+ * Internal struct used when compiling templates
+ */
+typedef struct ltm_placeholder {
+  const char *start;
+  const char *end;
+  struct {
+    const char *s;
+    size_t len;
+  } name;
+  ltm_placeholder_type type;
+} ltm_placeholder;
+
+/**
+ * The type of a template block
+ */
+typedef enum ltm_template_block_type {
+  ltm_template_block_type_literal = 0,
+  ltm_template_block_type_var,
+  ltm_template_block_type_nested,
+} ltm_template_block_type;
+
+/**
+ * A block in a template.
+ */
+typedef struct ltm_template_block {
+  ltm_template_block_type type;
+  struct {
+    void *ptr;
+    size_t len;
+  } data;
+} ltm_template_block;
+
+typedef struct ltm_template_block_name {
+  struct {
+    const char *s;
+    size_t len;
+  } name;
+  size_t index;
+} ltm_template_block_name;
+
+/**
+ * Represents a compiled template. A template consists of a list of blocks, of
+ * which some have names that can be indexed (e.g. variables, nested templates).
+ */
+struct ltm_template {
+  struct {
+    ltm_template_block *arr;
+    size_t len;
+  } blocks;
+  struct {
+    ltm_template_block_name *arr;
+    size_t len;
+  } names;
+};
+
+/**
+ * Allocate a new `ltm_template`.
+ */
+ltm_err ltm_template_init(ltm_template **out);
+
+/**
+ * Append a name to the template's list.
+ */
+ltm_err ltm_template_name_append(ltm_template *template, const char *s,
+                                 size_t len, size_t index);
+
+/**
+ * Append a block to the template's list.
+ */
+ltm_err ltm_template_block_append(ltm_template *template,
+                                  ltm_template_block_type type, void *data,
+                                  size_t len);
+
+typedef struct ltm_instance_block {
+  ltm_instance_block_type type;
+  ltm_data_fn fn;
+  struct {
+    void *ptr;
+    size_t len;
+  } data;
+  struct ltm_instance_block *next;
+} ltm_instance_block;
+
+ltm_err ltm_instance_block_init(ltm_instance_block **out);
+
+/**
+ * Add a new block to the instance with the given type.
+ */
+ltm_err ltm_instance_block_add(ltm_instance_block **out, ltm_instance *instance,
+                               const char *name, ltm_instance_block_type type);
+
+struct ltm_instance {
+  const ltm_template *template;
+  struct {
+    ltm_instance_block *head;
+    ltm_instance_block *tail;
+    ltm_instance_block *current;
+  } blocks;
+  ltm_instance_block ***vars;
+  // How many bytes of the current block have been written
+  size_t written;
+};
+
+ltm_err ltm_instance_init(ltm_instance **out);
+
+#endif

ltm/src/ltm_instance.c

@@ -0,0 +1,350 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "ltm/common.h"
+#include "ltm/template.h"
+#include "ltm/template_internal.h"
+
+ltm_err ltm_instance_block_init(ltm_instance_block **out) {
+  ltm_instance_block *block = calloc(1, sizeof(ltm_instance_block));
+
+  if (block == NULL) {
+    return ltm_err_failed_alloc;
+  }
+
+  *out = block;
+
+  return ltm_err_ok;
+}
+
+ltm_err ltm_instance_init(ltm_instance **out) {
+  ltm_instance *instance = calloc(1, sizeof(ltm_instance));
+
+  if (instance == NULL) {
+    return ltm_err_failed_alloc;
+  }
+
+  *out = instance;
+
+  return ltm_err_ok;
+}
+
+void ltm_instance_free(ltm_instance *instance) {
+  if (instance->vars != NULL) {
+    free(instance->vars);
+  }
+
+  ltm_instance_block *block = instance->blocks.head;
+
+  while (block != NULL) {
+    switch (block->type) {
+    case ltm_instance_block_type_buf_owned:
+      free(block->data.ptr);
+      break;
+    case ltm_instance_block_type_file_owned:
+      fclose(block->data.ptr);
+      break;
+    case ltm_instance_block_type_nested:
+      ltm_instance_free(block->data.ptr);
+      break;
+    case ltm_instance_block_type_file:
+    case ltm_instance_block_type_fn:
+    case ltm_instance_block_type_buf:;
+    }
+
+    ltm_instance_block *temp = block->next;
+    free(block);
+    block = temp;
+  }
+
+  free(instance);
+}
+
+ltm_err ltm_template_instantiate(ltm_instance **out,
+                                 const ltm_template *template) {
+  ltm_instance *instance;
+  LTM_RES(ltm_instance_init(&instance));
+
+  instance->template = template;
+
+  ltm_instance_block ***vars = NULL;
+
+  if (template->names.len > 0) {
+    vars = malloc(template->names.len * sizeof(ltm_instance_block **));
+
+    if (vars == NULL) {
+      ltm_instance_free(instance);
+
+      return ltm_err_failed_alloc;
+    }
+
+    instance->vars = vars;
+  }
+
+  for (size_t block_index = 0; block_index < template->blocks.len;
+       block_index++) {
+    ltm_template_block *template_block = &template->blocks.arr[block_index];
+
+    switch (template_block->type) {
+    case ltm_template_block_type_literal: {
+      ltm_instance_block *block;
+      LTM_RES2(ltm_instance_block_init(&block), ltm_instance_free(instance));
+
+      block->type = ltm_instance_block_type_buf;
+      block->data.ptr = template_block->data.ptr;
+      block->data.len = template_block->data.len;
+
+      if (instance->blocks.head == NULL) {
+        instance->blocks.head = block;
+        instance->blocks.tail = block;
+        instance->blocks.current = block;
+      } else {
+        instance->blocks.tail->next = block;
+        instance->blocks.tail = block;
+      }
+    } break;
+    case ltm_template_block_type_var:
+    case ltm_template_block_type_nested:
+      // Account for the possibility a template starts with a placeholder
+      *vars = instance->blocks.tail != NULL ? &instance->blocks.tail->next
+                                            : &instance->blocks.head;
+      vars++;
+      break;
+    }
+  }
+
+  *out = instance;
+
+  return ltm_err_ok;
+}
+
+ltm_err ltm_instance_block_add(ltm_instance_block **out, ltm_instance *instance,
+                               const char *name, ltm_instance_block_type type) {
+  const ltm_template *template = instance->template;
+
+  ltm_template_block_name *block_name = NULL;
+  size_t i = 0;
+
+  while (i < template->names.len) {
+    block_name = &template->names.arr[i];
+
+    if (strncmp(name, block_name->name.s, block_name->name.len) == 0) {
+      break;
+    }
+
+    i++;
+  }
+
+  if (i == template->names.len) {
+    return ltm_err_not_found;
+  }
+
+  ltm_template_block *template_block = &template->blocks.arr[block_name->index];
+  bool correct_type = false;
+
+  switch (type) {
+  case ltm_instance_block_type_nested:
+    correct_type = template_block->type == ltm_template_block_type_nested;
+    break;
+  case ltm_instance_block_type_buf:
+  case ltm_instance_block_type_buf_owned:
+  case ltm_instance_block_type_file:
+  case ltm_instance_block_type_file_owned:
+  case ltm_instance_block_type_fn:
+    correct_type = template_block->type == ltm_template_block_type_var;
+    break;
+  }
+
+  if (!correct_type) {
+    return ltm_err_wrong_block_type;
+  }
+
+  ltm_instance_block *block;
+  LTM_RES(ltm_instance_block_init(&block));
+
+  block->type = type;
+
+  // Insert the block in the linked list
+  block->next = *instance->vars[i];
+  *instance->vars[i] = block;
+  instance->vars[i] = &block->next;
+
+  *out = block;
+
+  return ltm_err_ok;
+}
+
+ltm_err ltm_instance_block_add_var(ltm_instance *instance, const char *name,
+                                   ltm_instance_block_type type, void *data,
+                                   size_t len) {
+  ltm_instance_block *block;
+  LTM_RES(ltm_instance_block_add(&block, instance, name, type));
+
+  block->data.ptr = data;
+  block->data.len = len;
+
+  return ltm_err_ok;
+}
+
+ltm_err ltm_instance_block_add_var_fn(ltm_instance *instance, const char *name,
+                                      ltm_data_fn fn, void *data, size_t len) {
+  ltm_instance_block *block;
+  LTM_RES(ltm_instance_block_add(&block, instance, name,
+                                 ltm_instance_block_type_fn));
+
+  block->fn = fn;
+  block->data.ptr = data;
+  block->data.len = len;
+
+  return ltm_err_ok;
+}
+
+ltm_err ltm_instance_block_add_nested(ltm_instance **out,
+                                      ltm_instance *instance,
+                                      const char *name) {
+  const ltm_template *template = instance->template;
+
+  ltm_template_block_name *block_name = NULL;
+  size_t i = 0;
+
+  while (i < template->names.len) {
+    block_name = &template->names.arr[i];
+
+    if (strncmp(name, block_name->name.s, block_name->name.len) == 0) {
+      break;
+    }
+
+    i++;
+  }
+
+  if (i == template->names.len) {
+    return ltm_err_not_found;
+  }
+
+  ltm_template_block *template_block = &template->blocks.arr[block_name->index];
+
+  if (template_block->type != ltm_template_block_type_nested) {
+    return ltm_err_wrong_block_type;
+  }
+
+  ltm_instance_block *block;
+  LTM_RES(ltm_instance_block_init(&block));
+
+  ltm_instance *nested;
+  LTM_RES2(ltm_template_instantiate(&nested, template_block->data.ptr),
+           free(block));
+
+  block->type = ltm_instance_block_type_nested;
+  block->data.ptr = nested;
+
+  // We insert the block in the linked list and replace its next pointer as the
+  // new attachment point for this variable
+  block->next = *instance->vars[i];
+  *instance->vars[i] = block;
+  instance->vars[i] = &block->next;
+
+  *out = nested;
+
+  return ltm_err_ok;
+}
+
+size_t ltm_instance_size(const ltm_instance *instance) {
+  size_t total = 0;
+  ltm_instance_block *block = instance->blocks.head;
+
+  while (block != NULL) {
+    switch (block->type) {
+    case ltm_instance_block_type_buf:
+    case ltm_instance_block_type_buf_owned:
+    case ltm_instance_block_type_file:
+    case ltm_instance_block_type_file_owned:
+    case ltm_instance_block_type_fn:
+      total += block->data.len;
+      break;
+    case ltm_instance_block_type_nested:
+      total += ltm_instance_size(block->data.ptr);
+      break;
+    }
+
+    block = block->next;
+  }
+
+  return total;
+}
+
+ltm_err ltm_instance_write(size_t *written, char *buf, size_t len,
+                           ltm_instance *instance) {
+  *written = 0;
+
+  while ((*written < len) && (instance->blocks.current != NULL)) {
+    ltm_instance_block *current = instance->blocks.current;
+
+    switch (current->type) {
+    case ltm_instance_block_type_buf:
+    case ltm_instance_block_type_buf_owned: {
+      size_t cap =
+          LTM_MIN(current->data.len - instance->written, len - *written);
+      memcpy(&buf[*written], &((char *)current->data.ptr)[instance->written],
+             cap);
+      *written += cap;
+      instance->written += cap;
+
+      if (instance->written == current->data.len) {
+        instance->blocks.current = current->next;
+        instance->written = 0;
+      }
+    } break;
+    case ltm_instance_block_type_file:
+    case ltm_instance_block_type_file_owned: {
+      size_t cap =
+          LTM_MIN(current->data.len - instance->written, len - *written);
+      size_t read = fread(&buf[*written], 1, cap, current->data.ptr);
+
+      if ((read == 0) && (ferror(current->data.ptr) != 0)) {
+        return ltm_err_failed_io;
+      }
+
+      *written += read;
+      instance->written += read;
+
+      if (instance->written == current->data.len) {
+        instance->blocks.current = current->next;
+        instance->written = 0;
+      }
+    } break;
+    case ltm_instance_block_type_fn: {
+      size_t cap =
+          LTM_MIN(current->data.len - instance->written, len - *written);
+      size_t fn_written = 0;
+      LTM_RES(current->fn(&fn_written, &buf[*written], cap, current->data.ptr));
+      *written += fn_written;
+      instance->written += fn_written;
+
+      if (instance->written == current->data.len) {
+        instance->blocks.current = current->next;
+        instance->written = 0;
+      }
+    } break;
+    case ltm_instance_block_type_nested: {
+      size_t nested_written = 0;
+      ltm_err res = ltm_instance_write(&nested_written, &buf[*written],
+                                       len - *written, current->data.ptr);
+      *written += nested_written;
+
+      switch (res) {
+      case ltm_err_done:
+        instance->blocks.current = current->next;
+        instance->written = 0;
+        break;
+      case ltm_err_ok:
+        break;
+      default:
+        return res;
+      }
+    } break;
+    }
+  }
+
+  return instance->blocks.current == NULL ? ltm_err_done : ltm_err_ok;
+}

ltm/src/ltm_template.c

@@ -0,0 +1,93 @@
+#include "ltm/template.h"
+#include "ltm/template_internal.h"
+
+ltm_err ltm_template_init(ltm_template **out) {
+  ltm_template *template = calloc(1, sizeof(ltm_template));
+
+  if (template == NULL) {
+    return ltm_err_failed_alloc;
+  }
+
+  *out = template;
+
+  return ltm_err_ok;
+}
+
+void ltm_template_free(ltm_template *template) {
+  if (template->blocks.len > 0) {
+    for (size_t i = 0; i < template->blocks.len; i++) {
+      ltm_template_block *block = &template->blocks.arr[i];
+
+      switch (block->type) {
+      case ltm_template_block_type_nested:
+        ltm_template_free(block->data.ptr);
+        break;
+      case ltm_template_block_type_var:
+      case ltm_template_block_type_literal:;
+      }
+    }
+
+    free(template->blocks.arr);
+  }
+
+  if (template->names.len > 0) {
+    free(template->names.arr);
+  }
+
+  free(template);
+}
+
+ltm_err ltm_template_name_append(ltm_template *template, const char *s,
+                                 size_t len, size_t index) {
+  ltm_template_block_name *names =
+      realloc(template->names.arr,
+              (template->names.len + 1) * sizeof(ltm_template_block_name));
+
+  if (names == NULL) {
+    return ltm_err_failed_alloc;
+  }
+
+  ltm_template_block_name *name = &names[template->names.len];
+
+  name->name.s = s;
+  name->name.len = len;
+  name->index = index;
+
+  template->names.arr = names;
+  template->names.len++;
+
+  return ltm_err_ok;
+}
+
+ltm_err ltm_template_block_append(ltm_template *template,
+                                  ltm_template_block_type type, void *data,
+                                  size_t len) {
+  ltm_template_block *blocks =
+      realloc(template->blocks.arr,
+              (template->blocks.len + 1) * sizeof(ltm_template_block));
+
+  if (blocks == NULL) {
+    return ltm_err_failed_alloc;
+  }
+
+  ltm_template_block *block = &blocks[template->blocks.len];
+
+  block->type = type;
+
+  switch (type) {
+  case ltm_template_block_type_literal:
+    block->data.ptr = data;
+    block->data.len = len;
+    break;
+  case ltm_template_block_type_nested:
+    block->data.ptr = data;
+    break;
+  // For the other cases, we explicitely ignore the data and len arguments
+  default:;
+  }
+
+  template->blocks.arr = blocks;
+  template->blocks.len++;
+
+  return ltm_err_ok;
+}

ltm/src/ltm_template_compile.c

@@ -0,0 +1,198 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "ltm/common.h"
+#include "ltm/template.h"
+#include "ltm/template_internal.h"
+
+static bool ltm_template_next_placeholder(ltm_placeholder *ph, const char *s,
+                                          size_t len) {
+  if (len == 0) {
+    return false;
+  }
+
+  ph->start = memchr(s, '{', len - 1);
+
+  if ((ph->start == NULL) || (ph->start[1] != '{')) {
+    return false;
+  }
+
+  size_t new_len = len - (ph->start - s);
+
+  // A template can never be valid without at least 5 characters
+  if (new_len < 5) {
+    ph->type = ltm_placeholder_type_invalid;
+
+    return true;
+  }
+
+  ph->end = memchr(ph->start + 2, '}', new_len - 3);
+
+  // Non-terminated placeholders aren't valid
+  if ((ph->end == NULL) || (ph->end[1] != '}')) {
+    ph->type = ltm_placeholder_type_invalid;
+
+    return true;
+  }
+
+  // End should point to final character
+  ph->end++;
+
+  // Parse the words
+  ph->name.s = ph->start + 2;
+
+  while ((*ph->name.s == ' ') && (ph->name.s != ph->end - 1)) {
+    ph->name.s++;
+  }
+
+  // Placeholder is empty
+  if (ph->name.s == ph->end - 1) {
+    ph->type = ltm_placeholder_type_invalid;
+
+    return true;
+  }
+
+  const char *ident = ph->name.s;
+
+  while ((*ident != ' ') && (ident != ph->end - 1)) {
+    ident++;
+  }
+
+  ph->name.len = ident - ph->name.s;
+
+  // Skip whitespace over to next word
+  while ((*ident == ' ') && (ident != ph->end - 1)) {
+    ident++;
+  }
+
+  if (ident == ph->end - 1) {
+    ph->type = ltm_placeholder_type_var;
+  } else {
+    // Further parse the identifier
+    const char *temp = ident;
+
+    while ((*temp != ' ') && (temp != ph->end - 1)) {
+      temp++;
+    }
+
+    size_t ident_len = temp - ident;
+
+    if (strncmp("start", ident, ident_len) == 0) {
+      ph->type = ltm_placeholder_type_nested_start;
+    } else if (strncmp("end", ident, ident_len) == 0) {
+      ph->type = ltm_placeholder_type_nested_end;
+    } else {
+      ph->type = ltm_placeholder_type_invalid;
+    }
+  }
+
+  return true;
+}
+
+ltm_err ltm_template_compile_n(ltm_template **out, const char *s, size_t len) {
+  ltm_template *template;
+  LTM_RES(ltm_template_init(&template));
+
+  ltm_placeholder ph;
+  bool in_nested = false;
+  const char *nested_start = NULL, *nested_name = NULL;
+  size_t nested_depth = 0, nested_name_len = 0;
+
+  size_t cur_nested_depth = 0;
+
+  while (ltm_template_next_placeholder(&ph, s, len)) {
+    // Add part before placeholder as literal
+    if (!in_nested && (ph.start != s)) {
+      LTM_RES2(ltm_template_block_append(template,
+                                         ltm_template_block_type_literal,
+                                         (void *)s, ph.start - s),
+               ltm_template_free(template));
+    }
+
+    switch (ph.type) {
+    // Invalid placeholders can be detected as early as possible
+    case ltm_placeholder_type_invalid:
+      ltm_template_free(template);
+
+      return ltm_err_invalid_template;
+    case ltm_placeholder_type_var:
+      if (!in_nested) {
+        LTM_RES2(ltm_template_block_append(
+                     template, ltm_template_block_type_var, NULL, 0),
+                 ltm_template_free(template));
+        LTM_RES2(ltm_template_name_append(template, ph.name.s, ph.name.len,
+                                          template->blocks.len - 1),
+                 ltm_template_free(template));
+      }
+      break;
+    case ltm_placeholder_type_nested_start:
+      if (!in_nested) {
+        nested_start = ph.end + 1;
+        nested_depth = cur_nested_depth;
+        nested_name = ph.name.s;
+        nested_name_len = ph.name.len;
+        in_nested = true;
+      }
+      cur_nested_depth++;
+      break;
+    case ltm_placeholder_type_nested_end:
+      // This means there's more nested end placeholders than nested starts
+      if (cur_nested_depth == 0) {
+        ltm_template_free(template);
+
+        return ltm_err_invalid_template;
+      }
+
+      cur_nested_depth--;
+
+      if (in_nested && (cur_nested_depth == nested_depth)) {
+        size_t nested_len = ph.start - nested_start;
+        ltm_template *nested_template;
+        LTM_RES2(
+            ltm_template_compile_n(&nested_template, nested_start, nested_len),
+            ltm_template_free(template));
+        LTM_RES(ltm_template_block_append(
+            template, ltm_template_block_type_nested, nested_template, 0));
+        LTM_RES2(ltm_template_name_append(template, nested_name,
+                                          nested_name_len,
+                                          template->blocks.len - 1),
+                 ltm_template_free(template));
+
+        in_nested = false;
+      }
+      // We encountered a nested end without a start
+      else if (!in_nested) {
+        ltm_template_free(template);
+
+        return ltm_err_invalid_template;
+      }
+      break;
+    }
+
+    len -= ph.end + 1 - s;
+    s = ph.end + 1;
+  }
+
+  // Unfinished nested
+  if (in_nested) {
+    ltm_template_free(template);
+
+    return ltm_err_invalid_template;
+  }
+
+  // Add remaining trailing literal
+  if (len > 0) {
+    LTM_RES2(ltm_template_block_append(
+                 template, ltm_template_block_type_literal, (void *)s, len),
+             ltm_template_free(template));
+  }
+
+  *out = template;
+
+  return ltm_err_ok;
+}
+
+ltm_err ltm_template_compile(ltm_template **out, const char *template) {
+  return ltm_template_compile_n(out, template, strlen(template));
+}

ltm/test/instance.c

@@ -0,0 +1,44 @@
+#include "test.h"
+
+#include "ltm/common.h"
+#include "ltm/template.h"
+#include "ltm/template_internal.h"
+
+void test_single_placeholder() {
+  const char *s = "Hello, {{ world }}!";
+
+  ltm_template *template;
+  TEST_ASSERT(ltm_template_compile(&template, s) == ltm_err_ok);
+
+  ltm_instance *instance;
+  TEST_CHECK(ltm_template_instantiate(&instance, template) == ltm_err_ok);
+
+  TEST_CHECK(ltm_instance_block_add_var(instance, "world", ltm_instance_block_type_buf, "World", 5) == ltm_err_ok);
+
+  TEST_CHECK(ltm_instance_size(instance) == 13);
+
+  char buf[13];
+
+  size_t written = 0;
+  TEST_CHECK(ltm_instance_write(&written, buf, 5, instance) == ltm_err_ok);
+  TEST_CHECK(written == 5);
+
+  written = 0;
+  TEST_CHECK(ltm_instance_write(&written, buf + 5, 5, instance) == ltm_err_ok);
+  TEST_CHECK(written == 5);
+
+  written = 0;
+  TEST_CHECK(ltm_instance_write(&written, buf + 10, 5, instance) == ltm_err_done);
+  TEST_CHECK(written == 3);
+
+  TEST_CHECK(strncmp(buf, "Hello, World!", 13) == 0);
+  TEST_DUMP("buf", buf, 13);
+
+  ltm_instance_free(instance);
+  ltm_template_free(template);
+}
+
+TEST_LIST = {
+  { "instance single placeholder", test_single_placeholder },
+  { NULL, NULL }
+};

ltm/test/template_compile.c

@@ -0,0 +1,118 @@
+#include "test.h"
+
+#include "ltm/common.h"
+#include "ltm/template.h"
+#include "ltm/template_internal.h"
+
+void test_single_placeholder() {
+  const char *s = "Hello, {{ world }}";
+
+  ltm_template *template;
+  TEST_CHECK(ltm_template_compile(&template, s) == ltm_err_ok);
+
+  TEST_CHECK(template->blocks.len == 2);
+
+  TEST_CHECK(template->blocks.arr[0].type == ltm_template_block_type_literal);
+  TEST_CHECK(template->blocks.arr[0].data.ptr == s);
+  TEST_CHECK(template->blocks.arr[0].data.len == 7);
+
+  TEST_CHECK(template->blocks.arr[1].type == ltm_template_block_type_var);
+
+  TEST_CHECK(template->names.len == 1);
+
+  TEST_CHECK(template->names.arr[0].name.s == s + 10);
+  TEST_CHECK(template->names.arr[0].name.len == 5);
+  TEST_CHECK(template->names.arr[0].index == 1);
+
+  ltm_template_free(template);
+}
+
+void test_single_placeholder_trailing() {
+  const char *s = "Hello, {{ world }}!";
+
+  ltm_template *template;
+  TEST_CHECK(ltm_template_compile(&template, s) == ltm_err_ok);
+
+  TEST_CHECK(template->blocks.len == 3);
+
+  TEST_CHECK(template->blocks.arr[0].type == ltm_template_block_type_literal);
+  TEST_CHECK(template->blocks.arr[0].data.ptr == s);
+  TEST_CHECK(template->blocks.arr[0].data.len == 7);
+
+  TEST_CHECK(template->blocks.arr[1].type == ltm_template_block_type_var);
+
+  TEST_CHECK(template->blocks.arr[2].type == ltm_template_block_type_literal);
+  TEST_CHECK(template->blocks.arr[2].data.ptr == s + 18);
+  TEST_CHECK(template->blocks.arr[2].data.len == 1);
+
+  TEST_CHECK(template->names.len == 1);
+
+  TEST_CHECK(template->names.arr[0].name.s == s + 10);
+  TEST_CHECK(template->names.arr[0].name.len == 5);
+  TEST_CHECK(template->names.arr[0].index == 1);
+
+  ltm_template_free(template);
+}
+
+void test_single_nested() {
+  const char *s = "abc {{ l start }}some content {{ var }} {{ l end }}";
+
+  ltm_template *template;
+  TEST_CHECK(ltm_template_compile(&template, s) == ltm_err_ok);
+
+  TEST_CHECK(template->names.len == 1);
+  TEST_CHECK(template->names.arr[0].name.s == s + 7);
+  TEST_CHECK(template->names.arr[0].name.len == 1);
+  TEST_CHECK(template->names.arr[0].index == 1);
+
+  TEST_CHECK(template->blocks.len == 2);
+
+  TEST_CHECK(template->blocks.arr[0].type == ltm_template_block_type_literal);
+  TEST_CHECK(template->blocks.arr[0].data.ptr == s);
+  TEST_CHECK(template->blocks.arr[0].data.len == 4);
+
+  TEST_CHECK(template->blocks.arr[1].type == ltm_template_block_type_nested);
+  ltm_template *nested_template = template->blocks.arr[1].data.ptr;
+
+  TEST_CHECK(nested_template->blocks.len == 3);
+  TEST_CHECK(nested_template->blocks.arr[0].type == ltm_template_block_type_literal);
+  TEST_CHECK(nested_template->blocks.arr[0].data.ptr == s + 17);
+  TEST_CHECK(nested_template->blocks.arr[0].data.len == 13);
+  TEST_CHECK(nested_template->blocks.arr[1].type == ltm_template_block_type_var);
+  TEST_CHECK(nested_template->blocks.arr[2].type == ltm_template_block_type_literal);
+  TEST_CHECK(nested_template->blocks.arr[2].data.ptr == s + 39);
+  TEST_CHECK(nested_template->blocks.arr[2].data.len == 1);
+
+  TEST_CHECK(nested_template->names.len == 1);
+  TEST_CHECK(nested_template->names.arr[0].name.s == s + 33);
+  TEST_CHECK(nested_template->names.arr[0].name.len == 3);
+  TEST_CHECK(nested_template->names.arr[0].index == 1);
+
+  ltm_template_free(template);
+}
+
+void test_unclosed_placeholder() {
+  ltm_template *template;
+
+  const char *s = "abc {{ var }";
+  TEST_CHECK(ltm_template_compile(&template, s) == ltm_err_invalid_template);
+
+  s = "abc {{ var ";
+  TEST_CHECK(ltm_template_compile(&template, s) == ltm_err_invalid_template);
+}
+
+void test_unclosed_nested() {
+  ltm_template *template;
+
+  const char *s = "abc {{ var start }} {{ hello }}";
+  TEST_CHECK(ltm_template_compile(&template, s) == ltm_err_invalid_template);
+}
+
+TEST_LIST = {
+  { "template single placeholder", test_single_placeholder },
+  { "template single placeholder trailing", test_single_placeholder_trailing },
+  { "template single nested", test_single_nested },
+  { "template unclosed placeholder", test_unclosed_placeholder },
+  { "template unclosed nested", test_unclosed_nested },
+  { NULL, NULL }
+};

src/lander/lander.c

@@ -3,6 +3,7 @@
 
 #include "lnm/common.h"
 #include "lsm/store.h"
+#include "ltm/template.h"
 
 #include "lander.h"
 
@@ -29,6 +30,12 @@ void lander_ctx_reset(lander_ctx *ctx) {
 
     ctx->entry = NULL;
   }
+
+  if (ctx->instance != NULL) {
+    ltm_instance_free(ctx->instance);
+
+    ctx->instance = NULL;
+  }
 }
 
 void lander_ctx_free(lander_ctx *ctx) { free(ctx); }

src/lander/lander_get.c

@@ -8,6 +8,7 @@
 #include "lsm/store.h"
 
 #include "lander.h"
+#include "ltm/template.h"
 
 static const char index_page[] =
     "<!DOCTYPE html>\n"
@@ -19,7 +20,7 @@ static const char index_page[] =
     "  </body>\n"
     "</html>\n";
 
-lnm_http_step_err lander_get_index(lnm_http_conn *conn) {
+lnm_http_step_err lander_get_root(lnm_http_conn *conn) {
   lnm_http_loop_ctx *ctx = conn->ctx;
 
   lnm_http_res_body_set_buf(&ctx->res, (char *)index_page,
@@ -72,13 +73,43 @@ lnm_err lander_entry_data_streamer(uint64_t *written, char *buf,
   return lnm_err_ok;
 }
 
-lnm_http_step_err lander_get_paste(lnm_http_conn *conn) {
+lnm_err lander_template_streamer(size_t *written, char *buf,
+                                 lnm_http_conn *conn, uint64_t offset,
+                                 uint64_t len) {
   lnm_http_loop_ctx *ctx = conn->ctx;
   lander_ctx *c_ctx = ctx->c;
 
-  lnm_http_res_body_set_fn(&ctx->res, lander_entry_data_streamer,
+  // TODO respect offset variable
+
+  ltm_instance_write(written, buf, len, c_ctx->instance);
+
+  return lnm_err_ok;
+}
+
+ltm_err lander_data_to_template(size_t *written, char *buf, size_t len,
+                                void *data) {
+  lsm_entry_handle *entry = data;
+
+  lsm_entry_data_read(written, buf, entry, len);
+
+  return ltm_err_ok;
+}
+
+lnm_http_step_err lander_get_paste(lnm_http_conn *conn) {
+  lnm_http_loop_ctx *ctx = conn->ctx;
+  lander_gctx *c_gctx = ctx->g->c;
+  lander_ctx *c_ctx = ctx->c;
+
+  ltm_template_instantiate(&c_ctx->instance, c_gctx->templates.paste);
+  /* ltm_instance_block_add_var(c_ctx->instance, ltm_instance_block_type_buf,
+   * lsm_str_ptr(c_ctx->entry)) */
+  ltm_instance_block_add_var_fn(c_ctx->instance, "paste",
+                                lander_data_to_template, c_ctx->entry,
                                 lsm_entry_data_len(c_ctx->entry));
-  lnm_http_res_add_header(&ctx->res, lnm_http_header_content_type, "text/plain",
+
+  lnm_http_res_body_set_fn(&ctx->res, lander_template_streamer,
+                           ltm_instance_size(c_ctx->instance));
+  lnm_http_res_add_header(&ctx->res, lnm_http_header_content_type, "text/html",
                           false);
 
   return lnm_http_step_err_done;
@@ -112,6 +143,93 @@ lnm_http_step_err lander_get_file(lnm_http_conn *conn) {
   return lnm_http_step_err_done;
 }
 
+lnm_http_step_err lander_get_index(lnm_http_conn *conn) {
+  lnm_http_loop_ctx *ctx = conn->ctx;
+  lander_gctx *c_gctx = ctx->g->c;
+  lander_ctx *c_ctx = ctx->c;
+
+  ltm_template_instantiate(&c_ctx->instance, c_gctx->templates.index);
+
+  const lsm_str *key;
+  lsm_entry_key(&key, c_ctx->entry);
+
+  ltm_instance_block_add_var(c_ctx->instance, "title_key",
+                             ltm_instance_block_type_buf,
+                             (void *)lsm_str_ptr(key), lsm_str_len(key));
+
+  lsm_str *prefix;
+  lsm_str_init_copy_n(&prefix, lsm_str_ptr(key), lsm_str_len(key));
+  lsm_str_append_c(prefix, "_", 1);
+
+  uint64_t prefix_len = lsm_str_len(prefix);
+
+  lsm_store_iterator *iter;
+  lsm_store_iter(&iter, c_gctx->store, prefix);
+
+  lsm_entry_handle *handle;
+  while (lsm_store_iter_next_read(&handle, iter) == lsm_error_ok) {
+    const lsm_str *entry_key;
+    lsm_entry_key(&entry_key, handle);
+
+    lander_entry_type t;
+    lsm_entry_attr_get_uint8_t((uint8_t *)&t, handle,
+                               lander_attr_type_entry_type);
+
+    ltm_instance *nested;
+
+    switch (t) {
+    case lander_entry_type_redirect:
+      ltm_instance_block_add_nested(&nested, c_ctx->instance, "redirect");
+
+      ltm_instance_block_add_var(
+          nested, "full_key", ltm_instance_block_type_buf,
+          (void *)lsm_str_ptr(entry_key), lsm_str_len(entry_key));
+      ltm_instance_block_add_var(nested, "short_key",
+                                 ltm_instance_block_type_buf,
+                                 (void *)(lsm_str_ptr(entry_key) + prefix_len),
+                                 lsm_str_len(entry_key) - prefix_len);
+      break;
+    case lander_entry_type_file:
+    case lander_entry_type_paste:
+      ltm_instance_block_add_nested(&nested, c_ctx->instance,
+                                    t == lander_entry_type_file ? "file"
+                                                                : "paste");
+
+      ltm_instance_block_add_var(
+          nested, "full_key", ltm_instance_block_type_buf,
+          (void *)lsm_str_ptr(entry_key), lsm_str_len(entry_key));
+
+      // Add the filename as the link name if known, or just the key otherwise
+      lsm_str *filename;
+      if (lsm_entry_attr_get(&filename, handle, lander_attr_type_file_name) ==
+          lsm_error_ok) {
+        ltm_instance_block_add_var(
+            nested, "filename", ltm_instance_block_type_buf,
+            (void *)lsm_str_ptr(filename), lsm_str_len(filename));
+      } else {
+        ltm_instance_block_add_var(
+            nested, "filename", ltm_instance_block_type_buf,
+            (void *)(lsm_str_ptr(entry_key) + prefix_len),
+            lsm_str_len(entry_key) - prefix_len);
+      }
+      break;
+    }
+
+    // TODO this should be done after writing the template
+    lsm_entry_close(handle);
+  }
+
+  lnm_http_res_body_set_fn(&ctx->res, lander_template_streamer,
+                           ltm_instance_size(c_ctx->instance));
+  lnm_http_res_add_header(&ctx->res, lnm_http_header_content_type, "text/html",
+                          false);
+
+  lsm_store_iter_free(iter);
+  lsm_str_free(prefix);
+
+  return lnm_http_step_err_done;
+}
+
 lnm_http_step_err lander_get_entry(lnm_http_conn *conn) {
   lnm_http_loop_ctx *ctx = conn->ctx;
   lander_ctx *c_ctx = ctx->c;
@@ -153,6 +271,9 @@ lnm_http_step_err lander_get_entry(lnm_http_conn *conn) {
   case lander_entry_type_file:
     res = lander_get_file(conn);
     break;
+  case lander_entry_type_index:
+    res = lander_get_index(conn);
+    break;
   }
 
   return res;

src/lander/lander_post.c

@@ -124,3 +124,21 @@ lnm_http_step_err lander_post_file(lnm_http_conn *conn) {
 
   return lnm_http_step_err_done;
 }
+
+lnm_http_step_err lander_post_index(lnm_http_conn *conn) {
+  lnm_http_loop_ctx *ctx = conn->ctx;
+  lander_ctx *c_ctx = ctx->c;
+
+  if (!lander_insert_entry(ctx)) {
+    return lnm_http_step_err_res;
+  }
+
+  lsm_entry_attr_insert_uint8_t(c_ctx->entry, lander_attr_type_entry_type,
+                                lander_entry_type_index);
+  /* lander_header_to_attr(ctx, "X-Lander-Content-Type", */
+  /*                       lander_attr_type_content_type); */
+  /* lander_header_to_attr(ctx, "X-Lander-Filename",
+   * lander_attr_type_file_name); */
+
+  return lnm_http_step_err_done;
+}

src/main.c

@@ -4,11 +4,46 @@
 
 #include "lnm/http/loop.h"
 #include "lnm/log.h"
+#include "ltm/template.h"
 
 #include "lander.h"
 #include "log.h"
 
 const char *lander_server = "lander/" LANDER_VERSION;
+const char *paste_template =
+    "<!doctype html>\n"
+    "<head><link rel=\"stylesheet\" "
+    "href=\"https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.9.0/build/"
+    "styles/stackoverflow-dark.min.css\">\n"
+    "<script "
+    "src=\"https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/"
+    "highlight.min.js\"></script>\n"
+    "<script>hljs.highlightAll();</script></head>\n"
+    "<body><h1>{{ header }}</h1><pre><code>{{ paste }}</code></pre></body>";
+
+const char *index_template =
+    "<!doctype html>\n"
+    "<body>\n"
+    "<h1>Index /{{ title_key }}</h1>\n"
+    "<h2>Redirects</h2>\n"
+    "<ul>\n"
+    "{{ redirect start }}\n"
+    "<li><a href=\"/{{ full_key }}\">{{ short_key }}</a></li>\n"
+    "{{ redirect end }}\n"
+    "</ul>\n"
+    "<h2>Files</h2>"
+    "<ul>\n"
+    "{{ file start }}\n"
+    "<li><a href=\"/{{ full_key }}\">{{ filename }}</a></li>\n"
+    "{{ file end }}\n"
+    "</ul>\n"
+    "<h2>Pastes</h2>\n"
+    "<ul>\n"
+    "{{ paste start }}\n"
+    "<li><a href=\"/{{ full_key }}\">{{ filename }}</a></li>\n"
+    "{{ paste end }}\n"
+    "</ul>\n"
+    "</body>\n";
 
 lnm_http_loop *loop_init(lander_gctx *gctx, const char *api_key) {
   lnm_http_loop *hl;
@@ -20,7 +55,7 @@ lnm_http_loop *loop_init(lander_gctx *gctx, const char *api_key) {
   lnm_http_loop_set_api_key(hl, api_key);
   lnm_http_loop_set_server(hl, lander_server);
 
-  lnm_http_step_init(&step, lander_get_index);
+  lnm_http_step_init(&step, lander_get_root);
   lnm_http_route_init_literal(&route, lnm_http_method_get, "/", step);
   lnm_http_loop_route_add(hl, route);
 
@@ -50,6 +85,14 @@ lnm_http_loop *loop_init(lander_gctx *gctx, const char *api_key) {
   lnm_http_step_append(&step, step, lander_stream_body_to_entry);
   lnm_http_loop_route_add(hl, route);
 
+  lnm_http_step_init(&step, lnm_http_loop_step_auth);
+  lnm_http_route_init_regex(&route, lnm_http_method_post, "^/i(l?)/([^/]+)$", 2,
+                            step);
+  lnm_http_step_append(&step, step, lander_post_index);
+  /* lnm_http_step_append(&step, step, lnm_http_loop_step_body_to_buf); */
+  /* lnm_http_step_append(&step, step, lander_post_redirect_body_to_attr); */
+  lnm_http_loop_route_add(hl, route);
+
   lnm_http_step_init(&step, lnm_http_loop_step_auth);
   lnm_http_route_init_regex(&route, lnm_http_method_delete, "^/([^/]+)$", 1,
                             step);
@@ -92,6 +135,9 @@ int main() {
   lander_gctx *c_gctx = lander_gctx_init();
   c_gctx->data_dir = data_dir_s;
 
+  ltm_template_compile(&c_gctx->templates.paste, paste_template);
+  ltm_template_compile(&c_gctx->templates.index, index_template);
+
   lsm_str *data_dir;
   lsm_str_init_copy(&data_dir, (char *)data_dir_s);