From 68f9227436f996b3e68f57bb49d3f35ebc8a874e Mon Sep 17 00:00:00 2001
From: Chewing_Bever <roosensjef@gmail.com>
Date: Sat, 27 May 2023 11:47:39 +0200
Subject: [PATCH] feat: decouple event loop from http

---
 .gitignore                                    |  2 +-
 include/event_loop.h                          | 58 +++++++-----------
 include/http_loop.h                           | 33 ++++++++++
 src/event_loop/event_loop.c                   | 12 ++--
 src/event_loop/event_loop_conn.c              | 23 ++-----
 src/event_loop/event_loop_io.c                | 50 ++--------------
 src/http_loop/http_loop.c                     | 60 +++++++++++++++++++
 .../http_loop_consts.c}                       |  3 -
 .../http_loop_parse.c}                        |  0
 .../http_loop_route.c}                        |  0
 .../http_loop_util.c}                         |  1 +
 src/main.c                                    |  6 +-
 12 files changed, 136 insertions(+), 112 deletions(-)
 create mode 100644 include/http_loop.h
 create mode 100644 src/http_loop/http_loop.c
 rename src/{http/http_consts.c => http_loop/http_loop_consts.c} (78%)
 rename src/{http/http_parse.c => http_loop/http_loop_parse.c} (100%)
 rename src/{http/http_route.c => http_loop/http_loop_route.c} (100%)
 rename src/{http/http_util.c => http_loop/http_loop_util.c} (95%)

diff --git a/.gitignore b/.gitignore
index 240d06c..c015b60 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,6 +2,6 @@ build/
 compile_commands.json
 
 # Data files
-lander.data
+lander.data*
 pastes/
 .cache/
diff --git a/include/event_loop.h b/include/event_loop.h
index 9376ece..1830cb2 100644
--- a/include/event_loop.h
+++ b/include/event_loop.h
@@ -5,27 +5,9 @@
 #include <stdint.h>
 #include <stdlib.h>
 
-#include "http_req.h"
-#include "trie.h"
-
 // Size of the read and write buffers for each connection, in bytes
 #define EVENT_LOOP_BUFFER_SIZE 1024
 
-typedef struct event_loop_gctx {
-  Trie *trie;
-} event_loop_gctx;
-
-event_loop_gctx *event_loop_gctx_init();
-
-typedef struct event_loop_ctx {
-  http_request req;
-  event_loop_gctx *g;
-} event_loop_ctx;
-
-event_loop_ctx *event_loop_ctx_init(event_loop_gctx *g);
-
-void event_loop_ctx_free(event_loop_ctx *ctx);
-
 /**
  * Represents an active connection managed by the event loop
  */
@@ -50,46 +32,52 @@ typedef struct event_loop_conn {
   // If true, the server will close the connection after the final write buffer
   // has been written
   bool close_after_write;
-  event_loop_ctx *ctx;
+  void *ctx;
 } event_loop_conn;
 
-/*
- * Initialize a new event_loop_conn struct
- */
-event_loop_conn *event_loop_conn_init(event_loop_gctx *g);
-
-void event_loop_conn_free(event_loop_conn *conn);
-
-/*
- * Process data on a connection
- */
-void event_loop_conn_io(event_loop_conn *conn);
-
 /*
  * Main struct object representing the event loop
  */
 typedef struct event_loop {
   event_loop_conn **connections;
   size_t connection_count;
-  event_loop_gctx *gctx;
+  // Global context passed to every connection
+  void *gctx;
+  // Function to initialize a context for a connection
+  void *(*ctx_init)(void *gctx);
+  // Function to free a context for a connection
+  void (*ctx_free)(void *ctx);
+  bool (*handle_data)(event_loop_conn *conn);
 } event_loop;
 
+/*
+ * Initialize a new event_loop_conn struct
+ */
+event_loop_conn *event_loop_conn_init(event_loop *el);
+
+void event_loop_conn_free(event_loop *el, event_loop_conn *conn);
+
+/*
+ * Process data on a connection
+ */
+void event_loop_conn_io(event_loop *el, event_loop_conn *conn);
+
 /*
  * Initialize a new event_loop struct
  */
-event_loop *event_loop_init(event_loop_gctx *g);
+event_loop *event_loop_init();
 
 /*
  * Place a new connection into the event loop's internal array.
  *
  * Returns -1 if the internal realloc failed
  */
-int event_loop_put(event_loop *loop, event_loop_conn *conn);
+int event_loop_put(event_loop *el, event_loop_conn *conn);
 
 /**
  * Accept a new connection for the given file descriptor.
  */
-int event_loop_accept(event_loop *loop, int fd);
+int event_loop_accept(event_loop *el, int fd);
 
 /*
  * Run the event loop. This function never returns.
diff --git a/include/http_loop.h b/include/http_loop.h
new file mode 100644
index 0000000..8291c81
--- /dev/null
+++ b/include/http_loop.h
@@ -0,0 +1,33 @@
+#ifndef LANDER_HTTP_LOOP
+#define LANDER_HTTP_LOOP
+
+#include "event_loop.h"
+#include "http_req.h"
+#include "trie.h"
+
+/*
+ * Global context passed to every connection using the same pointer
+ */
+typedef struct http_loop_gctx {
+  Trie *trie;
+} http_loop_gctx;
+
+http_loop_gctx *http_loop_gctx_init();
+
+/*
+ * Invidivual context initialized for every connection
+ */
+typedef struct http_loop_ctx {
+  http_request req;
+  http_loop_gctx *g;
+} http_loop_ctx;
+
+http_loop_ctx *http_loop_ctx_init(http_loop_gctx *g);
+
+void http_loop_ctx_free(http_loop_ctx *ctx);
+
+bool http_loop_handle_request(event_loop_conn *conn);
+
+event_loop *http_loop_init(http_loop_gctx *gctx);
+
+#endif
diff --git a/src/event_loop/event_loop.c b/src/event_loop/event_loop.c
index 4857d00..f648ca5 100644
--- a/src/event_loop/event_loop.c
+++ b/src/event_loop/event_loop.c
@@ -23,13 +23,12 @@ static int event_loop_fd_set_nb(int fd) {
   return 0;
 }
 
-event_loop *event_loop_init(event_loop_gctx *gctx) {
+event_loop *event_loop_init() {
   event_loop *el = calloc(sizeof(event_loop), 1);
 
   // No idea if this is a good starter value
   el->connections = calloc(sizeof(event_loop_conn), 16);
   el->connection_count = 16;
-  el->gctx = gctx;
 
   return el;
 }
@@ -71,7 +70,7 @@ int event_loop_accept(event_loop *el, int fd) {
   }
 
   // creating the struct Conn
-  event_loop_conn *conn = event_loop_conn_init(el->gctx);
+  event_loop_conn *conn = event_loop_conn_init(el);
 
   // Close the connectoin if we fail to allocate a connection struct
   if (conn == NULL) {
@@ -91,6 +90,8 @@ int event_loop_accept(event_loop *el, int fd) {
     return -4;
   }
 
+  debug("Connection established on fd %i", connfd);
+
   return 0;
 }
 
@@ -182,7 +183,7 @@ void event_loop_run(event_loop *el, int port) {
       if (poll_args[i].revents) {
         conn = el->connections[poll_args[i].fd];
 
-        event_loop_conn_io(conn);
+        event_loop_conn_io(el, conn);
 
         if (conn->state == event_loop_conn_state_end) {
           // client closed normally, or something bad happened.
@@ -190,7 +191,8 @@ void event_loop_run(event_loop *el, int port) {
           el->connections[conn->fd] = NULL;
 
           close(conn->fd);
-          event_loop_conn_free(conn);
+          debug("Connection closed on fd %i", conn->fd);
+          event_loop_conn_free(el, conn);
         }
       }
     }
diff --git a/src/event_loop/event_loop_conn.c b/src/event_loop/event_loop_conn.c
index 1c84e01..4791d8f 100644
--- a/src/event_loop/event_loop_conn.c
+++ b/src/event_loop/event_loop_conn.c
@@ -1,28 +1,13 @@
 #include "event_loop.h"
 
-event_loop_gctx *event_loop_gctx_init() {
-  event_loop_gctx *gctx = calloc(sizeof(event_loop_gctx), 1);
-
-  return gctx;
-}
-
-event_loop_ctx *event_loop_ctx_init(event_loop_gctx *g) {
-  event_loop_ctx *ctx = calloc(sizeof(event_loop_ctx), 1);
-  ctx->g = g;
-
-  return ctx;
-}
-
-void event_loop_ctx_free(event_loop_ctx *ctx) { free(ctx); }
-
-event_loop_conn *event_loop_conn_init(event_loop_gctx *g) {
+event_loop_conn *event_loop_conn_init(event_loop *el) {
   event_loop_conn *conn = calloc(sizeof(event_loop_conn), 1);
-  conn->ctx = event_loop_ctx_init(g);
+  conn->ctx = el->ctx_init(el->gctx);
 
   return conn;
 }
 
-void event_loop_conn_free(event_loop_conn *conn) {
-  event_loop_ctx_free(conn->ctx);
+void event_loop_conn_free(event_loop *el, event_loop_conn *conn) {
+  el->ctx_free(conn->ctx);
   free(conn);
 }
diff --git a/src/event_loop/event_loop_io.c b/src/event_loop/event_loop_io.c
index da8e940..ab116d6 100644
--- a/src/event_loop/event_loop_io.c
+++ b/src/event_loop/event_loop_io.c
@@ -1,19 +1,8 @@
 #include <errno.h>
-#include <fcntl.h>
-#include <netinet/in.h>
-#include <poll.h>
-#include <stdbool.h>
-#include <stdint.h>
-#include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
-#include <sys/socket.h>
 #include <unistd.h>
 
-#include "picohttpparser.h"
-
 #include "event_loop.h"
-#include "http.h"
 
 void event_loop_conn_io_res(event_loop_conn *conn) {
   while (1) {
@@ -52,43 +41,13 @@ void event_loop_conn_io_res(event_loop_conn *conn) {
   }
 }
 
-bool event_loop_handle_request(event_loop_conn *conn) {
-  // Prevents the request handler function from looping indefinitely without
-  // ever consuming new data
-  if (conn->rbuf_size - conn->rbuf_read == 0) {
-    return false;
-  }
-
-  http_parse_error res = http_parse_request(
-      &conn->ctx->req, (const char *)&conn->rbuf[conn->rbuf_read],
-      conn->rbuf_size - conn->rbuf_read);
-
-  if (res == http_parse_error_ok) {
-    // Perform the request
-    http_route(conn);
-  }
-  // Both in the case of an invalid HTTP request or one that's larger than the
-  // read buffer, we cannot determine when the next, possibly valid, HTTP
-  // request begins in the data stream. Therefore, we close the connection,
-  // even if additional pipelined requests are incoming.
-  else if (res == http_parse_error_invalid ||
-           (res == http_parse_error_incomplete &&
-            conn->rbuf_size == EVENT_LOOP_BUFFER_SIZE)) {
-    conn->state = event_loop_conn_state_end;
-  }
-
-  // TODO in highly concurrent situations, it might actually be better to always
-  // return false here, as this allows cycling better through all connections
-  return conn->state == event_loop_conn_state_req;
-}
-
 /**
  * Read new data into the read buffer. This command performs at most one
  * successful read syscall.
  *
  * Returns whether the function should be retried immediately or not.
  */
-void event_loop_conn_io_req(event_loop_conn *conn) {
+void event_loop_conn_io_req(event_loop *el, event_loop_conn *conn) {
   do {
     // Move remaining data to start of buffer
     memmove(conn->rbuf, &conn->rbuf[conn->rbuf_read],
@@ -135,23 +94,22 @@ void event_loop_conn_io_req(event_loop_conn *conn) {
     conn->rbuf_size += (size_t)res;
 
     // This loop allows processing multiple requests from a single read buffer
-    while (event_loop_handle_request(conn))
+    while (el->handle_data(conn))
       ;
   }
   // We can keep reading as long as we're in request mode
   while (conn->state == event_loop_conn_state_req);
 }
 
-void event_loop_conn_io(event_loop_conn *conn) {
+void event_loop_conn_io(event_loop *el, event_loop_conn *conn) {
   switch (conn->state) {
   case event_loop_conn_state_req:
-    event_loop_conn_io_req(conn);
+    event_loop_conn_io_req(el, conn);
     break;
   case event_loop_conn_state_res:
     event_loop_conn_io_res(conn);
     break;
   case event_loop_conn_state_end:
-    printf("we shouldn't be here\n");
     break;
   }
 }
diff --git a/src/http_loop/http_loop.c b/src/http_loop/http_loop.c
new file mode 100644
index 0000000..7f796de
--- /dev/null
+++ b/src/http_loop/http_loop.c
@@ -0,0 +1,60 @@
+#include "http_loop.h"
+#include "http.h"
+
+http_loop_gctx *http_loop_gctx_init() {
+  http_loop_gctx *gctx = calloc(sizeof(http_loop_gctx), 1);
+
+  return gctx;
+}
+
+http_loop_ctx *http_loop_ctx_init(http_loop_gctx *g) {
+  http_loop_ctx *ctx = calloc(sizeof(http_loop_ctx), 1);
+  ctx->g = g;
+
+  return ctx;
+}
+
+void http_loop_ctx_free(http_loop_ctx *ctx) { free(ctx); }
+
+bool http_loop_handle_request(event_loop_conn *conn) {
+  // Prevents the request handler function from looping indefinitely without
+  // ever consuming new data
+  if (conn->rbuf_size - conn->rbuf_read == 0) {
+    return false;
+  }
+
+  http_loop_ctx *ctx = conn->ctx;
+
+  http_parse_error res =
+      http_parse_request(&ctx->req, (const char *)&conn->rbuf[conn->rbuf_read],
+                         conn->rbuf_size - conn->rbuf_read);
+
+  if (res == http_parse_error_ok) {
+    // Perform the request
+    http_route(conn);
+  }
+  // Both in the case of an invalid HTTP request or one that's larger than the
+  // read buffer, we cannot determine when the next, possibly valid, HTTP
+  // request begins in the data stream. Therefore, we close the connection,
+  // even if additional pipelined requests are incoming.
+  else if (res == http_parse_error_invalid ||
+           (res == http_parse_error_incomplete &&
+            conn->rbuf_size == EVENT_LOOP_BUFFER_SIZE)) {
+    conn->state = event_loop_conn_state_end;
+  }
+
+  // TODO in highly concurrent situations, it might actually be better to always
+  // return false here, as this allows cycling better through all connections
+  return conn->state == event_loop_conn_state_req;
+}
+
+event_loop *http_loop_init(http_loop_gctx *gctx) {
+  event_loop *el = event_loop_init();
+
+  el->ctx_init = (void *(*)(void *))http_loop_ctx_init;
+  el->ctx_free = (void (*)(void *))http_loop_ctx_free;
+  el->handle_data = http_loop_handle_request;
+  el->gctx = gctx;
+
+  return el;
+}
diff --git a/src/http/http_consts.c b/src/http_loop/http_loop_consts.c
similarity index 78%
rename from src/http/http_consts.c
rename to src/http_loop/http_loop_consts.c
index b929c6d..9190d0a 100644
--- a/src/http/http_consts.c
+++ b/src/http_loop/http_loop_consts.c
@@ -1,16 +1,13 @@
 #include "http.h"
 
 const char http_404[] = "HTTP/1.1 404 Not Found\n"
-                        "Connection: close\n"
                         "Content-Length: 0\n\n";
 const size_t http_404_len = sizeof(http_404) - 1;
 
 const char http_405[] = "HTTP/1.1 405 Method Not Allowed\n"
-                        "Connection: close\n"
                         "Content-Length: 0\n\n";
 const size_t http_405_len = sizeof(http_405) - 1;
 
 const char http_500[] = "HTTP/1.1 500 Internal Server Error\n"
-                        "Connection: close\n"
                         "Content-Length: 0\n\n";
 const size_t http_500_len = sizeof(http_500) - 1;
diff --git a/src/http/http_parse.c b/src/http_loop/http_loop_parse.c
similarity index 100%
rename from src/http/http_parse.c
rename to src/http_loop/http_loop_parse.c
diff --git a/src/http/http_route.c b/src/http_loop/http_loop_route.c
similarity index 100%
rename from src/http/http_route.c
rename to src/http_loop/http_loop_route.c
diff --git a/src/http/http_util.c b/src/http_loop/http_loop_util.c
similarity index 95%
rename from src/http/http_util.c
rename to src/http_loop/http_loop_util.c
index 4b916e7..0289b62 100644
--- a/src/http/http_util.c
+++ b/src/http_loop/http_loop_util.c
@@ -1,4 +1,5 @@
 #include "http.h"
+#include "string.h"
 
 void http_write_standard_response(event_loop_conn *conn,
                                   http_response_type type) {
diff --git a/src/main.c b/src/main.c
index 5bbe18d..3fa415d 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,6 +1,6 @@
 #include <stdio.h>
 
-#include "event_loop.h"
+#include "http_loop.h"
 #include "log.h"
 
 int main() {
@@ -17,9 +17,9 @@ int main() {
 
   info("Trie initialized and populated with %i entries", count);
 
-  event_loop_gctx *gctx = event_loop_gctx_init();
+  http_loop_gctx *gctx = http_loop_gctx_init();
   gctx->trie = trie;
-  event_loop *el = event_loop_init(gctx);
+  event_loop *el = http_loop_init(gctx);
 
   event_loop_run(el, 8000);
 }