feat(lnm): add most of the writing code

lnm/include/lnm/common.h

@@ -17,6 +17,9 @@
     }                                                                          \
   }
 
+#define LNM_MIN(x, y) ((x) < (y) ? (x) : (y))
+#define LNM_MAX(x, y) ((x) > (y) ? (x) : (y))
+
 typedef enum {
   lnm_err_ok = 0,
   lnm_err_failed_alloc,
@@ -26,4 +29,12 @@ typedef enum {
   lnm_err_bad_regex
 } lnm_err;
 
+typedef struct lnm_loop lnm_http_loop;
+
+typedef struct lnm_loop_conn lnm_http_conn;
+
+typedef struct lnm_http_step lnm_http_step;
+
+typedef struct lnm_http_route lnm_http_route;
+
 #endif

lnm/include/lnm/http/loop.h

@@ -7,14 +7,6 @@
 #include "lnm/http/req.h"
 #include "lnm/http/res.h"
 
-typedef struct lnm_loop lnm_http_loop;
-
-typedef struct lnm_loop_conn lnm_http_conn;
-
-typedef struct lnm_http_step lnm_http_step;
-
-typedef struct lnm_http_route lnm_http_route;
-
 typedef enum lnm_http_step_err {
   lnm_http_step_err_done = 0,
   lnm_http_step_err_io_needed,

lnm/include/lnm/http/res.h

@@ -2,9 +2,17 @@
 #define LNM_HTTP_RES
 
 #include <stdbool.h>
+#include <stdio.h>
 
+#include "lnm/common.h"
 #include "lnm/http/consts.h"
 
+typedef lnm_err (*data_fn)(size_t *written, char *buf, lnm_http_conn *conn,
+                           size_t offset, size_t len);
+
+/**
+ * Linked list elements used to store the response headers
+ */
 typedef struct lnm_http_res_header {
   struct {
     char *s;
@@ -19,12 +27,85 @@ typedef struct lnm_http_res_header {
   struct lnm_http_res_header *next;
 } lnm_http_res_header;
 
+typedef enum lnm_http_res_body_type {
+  lnm_http_res_body_type_file = 0,
+  lnm_http_res_body_type_buf,
+  lnm_http_res_body_type_fn,
+} lnm_http_res_body_type;
+
 typedef struct lnm_http_res {
   lnm_http_status status;
   struct {
     lnm_http_res_header *head;
     lnm_http_res_header *current;
   } headers;
+  struct {
+    struct {
+      char *buf;
+      FILE *f;
+      data_fn fn;
+    } data;
+    size_t len;
+    bool owned;
+    lnm_http_res_body_type type;
+  } body;
+  // General-purpose; meaning depends on the current state
+  size_t written;
 } lnm_http_res;
 
+/**
+ * Add a new header of a known type to the response
+ *
+ * @param type type of header
+ * @param value null-terminated string containing the value of the header
+ * @param value_owned whether to take ownership of the value pointer; if false,
+ * free'ing the buffer is the caller's responsibility
+ */
+lnm_err lnm_http_res_add_header(lnm_http_res *res, lnm_http_header type,
+                                char *value, bool value_owned);
+
+/**
+ * Add a new header of a known type to the response with a given value length.
+ *
+ * @param type type of header
+ * @param value string of length `value_len` containing the value of the header
+ * @param value_len length of value
+ * @param value_owned whether to take ownership of the value pointer; if false,
+ * free'ing the buffer is the caller's responsibility
+ */
+lnm_err lnm_http_res_add_header_len(lnm_http_res *res, lnm_http_header type,
+                                    char *value, size_t value_len,
+                                    bool value_owned);
+
+/**
+ * Set the request body to the given file pointer.
+ *
+ * @param res response to modify
+ * @param f file pointer to use as data
+ * @param len expected length of the file
+ * @param owned whether to take ownership of the file pointer
+ */
+void lnm_http_res_body_set_file(lnm_http_res *res, FILE *f, size_t len,
+                                bool owned);
+
+/**
+ * Set the request body to the given buffer.
+ *
+ * @param res response to modify
+ * @param buf buffer to use as data
+ * @param len length of the buffer
+ * @param owned whether to take ownership of the file pointer
+ */
+void lnm_http_res_body_set_buf(lnm_http_res *res, char *buf, size_t len,
+                               bool owned);
+
+/**
+ * Set the request body to be read from the given data function.
+ *
+ * @param res response to modify
+ * @param fn data reader function
+ * @param len expected length of the response
+ */
+void lnm_http_res_body_set_fn(lnm_http_res *res, data_fn fn, size_t len);
+
 #endif