Prevent file descriptor leak

docs/changelog.md

@@ -7,6 +7,8 @@ Note: releases are listed from latest to oldest.
 - Fixed a bug when loading APNG files with reduced frames
 - Fixed a bug in the GIF compressor that would generate invalid compressed frame data when a code size increase and
   reduction occured at the same time
+- Fixed a file descriptor leak that would keep an open `FILE *` if a `PLUM_ERR_FILE_ERROR` error was raised while
+  reading from a file
 - Ensured that the `PLUM_FILENAME`, `PLUM_BUFFER` and `PLUM_CALLBACK` constants are always `size_t` as documented
 - Enforced the size limitation on the value returned by a callback when using the `PLUM_CALLBACK` loading/storing mode
 - Handled out-of-palette background colors when generating a GIF file, ensuring that they would never cause the

src/load.c

@@ -33,6 +33,7 @@ struct plum_image * plum_load_image_limited (const void * restrict buffer, size_
     else
       update_loaded_palette(context, flags);
   done:
+  if (context -> file) fclose(context -> file);
   if (error) *error = context -> status;
   struct plum_image * image = context -> image;
   if (context -> status) {
@@ -94,24 +95,19 @@ void prepare_image_buffer_data (struct context * context, const void * restrict
 }
 
 void load_file (struct context * context, const char * filename) {
-  FILE * fp = fopen(filename, "rb");
-  if (!fp) throw(context, PLUM_ERR_FILE_INACCESSIBLE);
+  context -> file = fopen(filename, "rb");
+  if (!context -> file) throw(context, PLUM_ERR_FILE_INACCESSIBLE);
   size_t allocated;
   char * buffer = resize_read_buffer(context, NULL, &allocated);
-  size_t size = fread(buffer, 1, allocated, fp);
-  if (ferror(fp)) {
-    fclose(fp);
-    throw(context, PLUM_ERR_FILE_ERROR);
-  }
-  while (!feof(fp)) {
+  size_t size = fread(buffer, 1, allocated, context -> file);
+  if (ferror(context -> file)) throw(context, PLUM_ERR_FILE_ERROR);
+  while (!feof(context -> file)) {
     if ((allocated - size) < 0x4000) buffer = resize_read_buffer(context, buffer, &allocated);
-    size += fread(buffer + size, 1, 0x4000, fp);
-    if (ferror(fp)) {
-      fclose(fp);
-      throw(context, PLUM_ERR_FILE_ERROR);
-    }
+    size += fread(buffer + size, 1, 0x4000, context -> file);
+    if (ferror(context -> file)) throw(context, PLUM_ERR_FILE_ERROR);
   }
-  fclose(fp);
+  fclose(context -> file);
+  context -> file = NULL;
   context -> data = ctxrealloc(context, buffer, size);
   context -> size = size;
 }

src/store.c

@@ -41,32 +41,30 @@ size_t plum_store_image (const struct plum_image * image, void * restrict buffer
   }
   result = output_size;
   done:
+  if (context -> file) fclose(context -> file);
   if (error) *error = context -> status;
   destroy_allocator_list(context -> allocator);
   return result;
 }
 
 void write_generated_image_data_to_file (struct context * context, const char * filename) {
-  FILE * fp = fopen(filename, "wb");
-  if (!fp) throw(context, PLUM_ERR_FILE_INACCESSIBLE);
+  context -> file = fopen(filename, "wb");
+  if (!context -> file) throw(context, PLUM_ERR_FILE_INACCESSIBLE);
   const struct data_node * node;
   for (node = context -> output; node -> previous; node = node -> previous);
   while (node) {
     const unsigned char * data = node -> data;
     size_t size = node -> size;
     while (size) {
-      unsigned count = fwrite(data, 1, (size > 0x4000) ? 0x4000 : size, fp);
-      if (count) {
-        data += count;
-        size -= count;
-      } else {
-        fclose(fp);
-        throw(context, PLUM_ERR_FILE_ERROR);
-      }
+      unsigned count = fwrite(data, 1, (size > 0x4000) ? 0x4000 : size, context -> file);
+      if (ferror(context -> file) || !count) throw(context, PLUM_ERR_FILE_ERROR);
+      data += count;
+      size -= count;
     }
     node = node -> next;
   }
-  fclose(fp);
+  fclose(context -> file);
+  context -> file = NULL;
 }
 
 void write_generated_image_data_to_callback (struct context * context, const struct plum_callback * callback) {

src/struct.h

@@ -1,3 +1,4 @@
+#include <stdio.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <setjmp.h>
@@ -36,6 +37,7 @@ struct context {
     struct plum_image * image;
     const struct plum_image * source;
   };
+  FILE * file;
   jmp_buf target;
 };