Refactor HTTP request parsing to return detailed status codes

Updated the `parse_http_request` functions to return specific status codes instead of void. This enhances error handling by providing more detailed information about the nature of any parsing failures. Additionally, improved memory allocation checks and cleaned up null pointer validations for better code reliability.

src/tiny_http/tiny_http_server_lib.c

@@ -8,6 +8,16 @@
 #include <stdlib.h>
 #include <string.h>
 
+enum parse_http_request_status {
+    PARSE_OK = 0,
+    E_REQ_IS_NULL = -11,
+    E_MALFORMED_HTTP_HEADER = 1,
+    E_ALLOC_MEM_FOR_HEADERS = 2,
+    E_HTTP_METHOD_NOT_SUPPORTED = 3,
+    E_MALFORMED_HTTP_REQUEST_LINE = 4,
+    E_HTTP_VERSION_NOT_SUPPORTED = 5,
+};
+
 
 /**
  * Frees the memory allocated for the given HTTP request and its components.
@@ -65,41 +75,34 @@ ssize_t get_body_size_from_header(const http_header *const *const headers, const
  * @param request the http_request object being parsed
  * @param ptr the http packet stream scan ptr
  */
-void parse_http_request_body(
-    const uint8_t * const http_packet,
+enum parse_http_request_status parse_http_request_body(
+    const uint8_t *const http_packet,
     const size_t http_packet_len,
     http_request *request,
     const size_t *ptr) {
     if (request == nullptr) {
         fprintf(stderr, "Error: null request\n");
         fflush(stderr);
-        return;
+        return E_REQ_IS_NULL;
     }
     if (*ptr < http_packet_len) {
-        const ssize_t body_len_from_header = request != nullptr && request->headers != nullptr ? get_body_size_from_header(
-            (const http_header * const * const) request->headers,
-            request->headers_cnt) : 0;
+        const ssize_t body_len_from_header = request != nullptr && request->headers != nullptr
+                                                 ? get_body_size_from_header(
+                                                     (const http_header * const * const) request->headers,
+                                                     request->headers_cnt)
+                                                 : 0;
         if (body_len_from_header >= 0) {
             request->body_len = body_len_from_header;
         } else {
             request->body_len = http_packet_len - *ptr;
         }
         request->body = (uint8_t *) strndup((char *) http_packet + *ptr, request->body_len);
     }
+    return PARSE_OK;
 }
 
-enum parse_http_request_status {
-    PARSE_OK = 0,
-    E_REQ_IS_NULL = -11,
-    E_MALFORMED_HTTP_HEADER = 1,
-    E_ALLOC_MEM_FOR_HEADERS = 2,
-    E_HTTP_METHOD_NOT_SUPPORTED = 3,
-    E_MALFORMED_HTTP_REQUEST_LINE = 4,
-    E_HTTP_VERSION_NOT_SUPPORTED = 5,
-};
-
 enum parse_http_request_status parse_http_request_headers(
-    const uint8_t * const http_packet,
+    const uint8_t *const http_packet,
     const size_t http_packet_len,
     http_request *request,
     size_t *ptr) {
@@ -133,7 +136,8 @@ enum parse_http_request_status parse_http_request_headers(
         }
         const size_t header_value_start = *ptr;
         size_t header_value_len = 0;
-        for (int iter_cnt = 0; *ptr < http_packet_len && iter_cnt < MAX_HTTP_HEADER_VALUE_LENGTH; (*ptr)++, iter_cnt++) {
+        for (int iter_cnt = 0; *ptr < http_packet_len && iter_cnt < MAX_HTTP_HEADER_VALUE_LENGTH;
+             (*ptr)++, iter_cnt++) {
             if (http_packet[(*ptr)] == '\r' && http_packet[*ptr + 1] == '\n') {
                 header_value_len = *ptr - header_value_start;
                 break;
@@ -165,10 +169,11 @@ enum parse_http_request_status parse_http_request_headers(
 }
 
 enum parse_http_request_status parse_http_request_line_from_packet(
-    const uint8_t * const http_packet,
+    const uint8_t *const http_packet,
     const size_t http_packet_len,
     http_request *request,
     size_t *ptr) {
+    if (request == nullptr) return E_REQ_IS_NULL;
     size_t start_uri = 0;
     if (strncmp((char *) http_packet, "GET", 3) == 0) {
         *ptr += 4; // "GET " - 4
@@ -228,29 +233,39 @@ enum parse_http_request_status parse_http_request_line_from_packet(
 }
 
 http_request *parse_http_request(const uint8_t *const http_packet, const size_t http_packet_len) {
-    http_request *request = calloc(1, sizeof(http_request));
     if (http_packet != nullptr && http_packet_len <= 5) {
         fprintf(stderr, "cannot parse http request as it appears empty");
         fflush(stderr);
-        destroy_http_request(request);
+        return nullptr;
+    }
+    http_request *request = calloc(1, sizeof(http_request));
+    if (request == nullptr) {
+        fprintf(stderr, "cannot allocate memory for new http request");
+        fflush(stderr);
         return nullptr;
     }
     size_t ptr = 0;
+
     const enum parse_http_request_status request_line_parse_status =
-        parse_http_request_line_from_packet(http_packet, http_packet_len, request, &ptr);
+            parse_http_request_line_from_packet(http_packet, http_packet_len, request, &ptr);
     if (request_line_parse_status != PARSE_OK) {
         destroy_http_request(request);
         return nullptr;
     }
 
-    const enum parse_http_request_status parse_status =
-        parse_http_request_headers(http_packet, http_packet_len, request, &ptr);
-    if (parse_status != PARSE_OK) {
+    const enum parse_http_request_status headers_parse_status =
+            parse_http_request_headers(http_packet, http_packet_len, request, &ptr);
+    if (headers_parse_status != PARSE_OK) {
         destroy_http_request(request);
         return nullptr;
     }
 
-    parse_http_request_body(http_packet, http_packet_len, request, &ptr);
+    const enum parse_http_request_status body_parse_status =
+            parse_http_request_body(http_packet, http_packet_len, request, &ptr);
+    if (body_parse_status != PARSE_OK) {
+        destroy_http_request(request);
+        return nullptr;
+    }
 
     return request;
 }