Reduce amount of leaked memory by libmagic

libmagic always leaks 48 bytes. Now we leak those bytes only once instead of
every content type detection.

Signed-off-by: Sebastian Ramacher <sebastian+dev@ramacher.at>

zathura/content-type.c

@@ -17,14 +17,23 @@
 #include <glib.h>
 #include <gio/gio.h>
 
-/** Read a most GT_MAX_READ bytes before falling back to file. */
-static const size_t GT_MAX_READ = 1 << 16;
+struct zathura_content_type_context_s
+{
+#ifdef WITH_MAGIC
+  magic_t magic;
+#endif
+};
+
+zathura_content_type_context_t*
+zathura_content_type_new(void)
+{
+  zathura_content_type_context_t* context =
+    g_try_malloc0(sizeof(zathura_content_type_context_t));
+  if (context == NULL) {
+    return NULL;
+  }
 
 #ifdef WITH_MAGIC
-static const char*
-guess_type_magic(const char* path) {
-  const char* mime_type = NULL;
-
   /* creat magic cookie */
   const int flags =
     MAGIC_MIME_TYPE |
@@ -36,31 +45,63 @@ guess_type_magic(const char* path) {
   magic_t magic = magic_open(flags);
   if (magic == NULL) {
     girara_debug("failed creating the magic cookie");
-    goto cleanup;
+    return context;
   }
 
   /* ... and load mime database */
   if (magic_load(magic, NULL) < 0) {
     girara_debug("failed loading the magic database: %s", magic_error(magic));
-    goto cleanup;
+    magic_close(magic);
+    return context;
   }
 
+  context->magic = magic;
+#endif
+
+  return context;
+}
+
+void
+zathura_content_type_free(zathura_content_type_context_t* context)
+{
+  if (context == NULL) {
+    return;
+  }
+
+#ifdef WITH_MAGIC
+  if (context->magic != NULL) {
+    magic_close(context->magic);
+  }
+#endif
+
+  g_free(context);
+}
+
+
+/** Read a most GT_MAX_READ bytes before falling back to file. */
+static const size_t GT_MAX_READ = 1 << 16;
+
+#ifdef WITH_MAGIC
+static const char*
+guess_type_magic(zathura_content_type_context_t* context, const char* path)
+{
+  if (context == NULL || context->magic == NULL) {
+    return NULL;
+  }
+
+  const char* mime_type = NULL;
+
   /* get the mime type */
-  mime_type = magic_file(magic, path);
+  mime_type = magic_file(context->magic, path);
   if (mime_type == NULL) {
-    girara_debug("failed guessing filetype: %s", magic_error(magic));
-    goto cleanup;
+    girara_debug("failed guessing filetype: %s", magic_error(context->magic));
+    return NULL;
   }
   /* dup so we own the memory */
   mime_type = g_strdup(mime_type);
 
   girara_debug("magic detected filetype: %s", mime_type);
 
-cleanup:
-  if (magic != NULL) {
-    magic_close(magic);
-  }
-
   return mime_type;
 }
 
@@ -71,7 +112,9 @@ guess_type_file(const char* UNUSED(path))
 }
 #else
 static const char*
-guess_type_magic(const char* UNUSED(path)) {
+guess_type_magic(zathura_content_type_context_t* UNUSED(context),
+                 const char* UNUSED(path))
+{
   return NULL;
 }
 
@@ -161,10 +204,11 @@ guess_type_glib(const char* path)
 }
 
 const char*
-guess_content_type(const char* path)
+zathura_content_type_guess(zathura_content_type_context_t* context,
+                           const char* path)
 {
   /* try libmagic first */
-  const char* content_type = guess_type_magic(path);
+  const char* content_type = guess_type_magic(context, path);
   if (content_type != NULL) {
     return content_type;
   }

zathura/content-type.h

@@ -3,6 +3,22 @@
 #ifndef ZATHURA_CONTENT_TYPE_H
 #define ZATHURA_CONTENT_TYPE_H
 
+#include "types.h"
+
+/**
+ * Create new context for MIME type detection.
+ *
+ * @return new context
+ */
+zathura_content_type_context_t* zathura_content_type_new(void);
+
+/**
+ * Free MIME type detection context.
+ *
+ * @param context The context.
+ */
+void zathura_content_type_free(zathura_content_type_context_t* context);
+
 /**
  * "Guess" the content type of a file. Various methods are tried depending on
  * the available libraries.
@@ -10,6 +26,7 @@
  * @param path file name
  * @return content type of path
  */
-const char* guess_content_type(const char* path);
+const char* zathura_content_type_guess(zathura_content_type_context_t* context,
+                                       const char* path);
 
 #endif

zathura/document.c

@@ -61,10 +61,10 @@ check_set_error(zathura_error_t* error, zathura_error_t code) {
 }
 
 zathura_document_t*
-zathura_document_open(zathura_plugin_manager_t* plugin_manager, const char*
-                      path, const char *uri, const char* password, zathura_error_t* error)
+zathura_document_open(zathura_t* zathura, const char* path, const char* uri,
+                      const char* password, zathura_error_t* error)
 {
-  if (path == NULL) {
+  if (zathura == NULL || path == NULL) {
     return NULL;
   }
 
@@ -87,14 +87,14 @@ zathura_document_open(zathura_plugin_manager_t* plugin_manager, const char*
     goto error_free;
   }
 
-  content_type = guess_content_type(real_path);
+  content_type = zathura_content_type_guess(zathura->content_type_context, real_path);
   if (content_type == NULL) {
     girara_error("Could not determine file type.");
     check_set_error(error, ZATHURA_ERROR_UNKNOWN);
     goto error_free;
   }
 
-  plugin = zathura_plugin_manager_get_plugin(plugin_manager, content_type);
+  plugin = zathura_plugin_manager_get_plugin(zathura->plugins.manager, content_type);
 
   if (plugin == NULL) {
     girara_error("Unknown file type: '%s'", content_type);

zathura/document.h

@@ -11,14 +11,14 @@
 /**
  * Open the document
  *
- * @param plugin_manager The plugin manager
+ * @param plugin_manager The zathura instance
  * @param path Path to the document
  * @param password Password of the document or NULL
  * @param error Optional error parameter
  * @return The document object and NULL if an error occurs
  */
-zathura_document_t* zathura_document_open(zathura_plugin_manager_t*
-    plugin_manager, const char* path, const char *uri, const char* password, zathura_error_t*
+zathura_document_t* zathura_document_open(zathura_t* zathura,
+    const char* path, const char *uri, const char* password, zathura_error_t*
     error);
 
 /**

zathura/types.h

@@ -255,4 +255,9 @@ zathura_document_information_entry_new(zathura_document_information_type_t
  */
 void zathura_document_information_entry_free(zathura_document_information_entry_t* entry);
 
+/**
+ * Context for MIME type detection
+ */
+typedef struct zathura_content_type_context_s zathura_content_type_context_t;
+
 #endif // TYPES_H

zathura/utils.c

@@ -52,12 +52,14 @@ file_valid_extension(zathura_t* zathura, const char* path)
     return false;
   }
 
-  const gchar* content_type = guess_content_type(path);
+  const gchar* content_type =
+    zathura_content_type_guess(zathura->content_type_context, path);
   if (content_type == NULL) {
     return false;
   }
 
-  zathura_plugin_t* plugin = zathura_plugin_manager_get_plugin(zathura->plugins.manager, content_type);
+  zathura_plugin_t* plugin =
+    zathura_plugin_manager_get_plugin(zathura->plugins.manager, content_type);
   g_free((void*)content_type);
 
   return (plugin == NULL) ? false : true;

zathura/zathura.c

@@ -43,6 +43,7 @@
 #include "dbus-interface.h"
 #include "css-definitions.h"
 #include "synctex.h"
+#include "content-type.h"
 
 typedef struct zathura_document_info_s {
   zathura_t* zathura;
@@ -103,6 +104,9 @@ zathura_create(void)
   zathura->signals.sigterm = g_unix_signal_add(SIGTERM, zathura_signal_sigterm, zathura);
 #endif
 
+  /* MIME type detection */
+  zathura->content_type_context = zathura_content_type_new();
+
   zathura->ui.session->global.data = zathura;
 
   return zathura;
@@ -376,6 +380,9 @@ zathura_free(zathura_t* zathura)
 
   document_close(zathura, false);
 
+  /* MIME type detection */
+  zathura_content_type_free(zathura->content_type_context);
+
 #ifdef G_OS_UNIX
   if (zathura->signals.sigterm > 0) {
     g_source_remove(zathura->signals.sigterm);
@@ -760,7 +767,7 @@ document_open(zathura_t* zathura, const char* path, const char* uri, const char*
 
   gchar* file_uri = NULL;
   zathura_error_t error = ZATHURA_ERROR_OK;
-  zathura_document_t* document = zathura_document_open(zathura->plugins.manager, path, uri, password, &error);
+  zathura_document_t* document = zathura_document_open(zathura, path, uri, password, &error);
 
   if (document == NULL) {
     if (error == ZATHURA_ERROR_INVALID_PASSWORD) {

zathura/zathura.h

@@ -6,7 +6,9 @@
 #include <stdbool.h>
 #include <girara/types.h>
 #include <gtk/gtk.h>
+#ifdef GDK_WINDOWING_X11
 #include <gtk/gtkx.h>
+#endif
 #include "macros.h"
 #include "types.h"
 
@@ -222,6 +224,11 @@ struct zathura_s
       double zoom;
     } toggle_presentation_mode;
   } shortcut;
+
+  /**
+   * Context for MIME type detection
+   */
+  zathura_content_type_context_t* content_type_context;
 };
 
 /**