The Tor Browser: image/decoders/icon/gtk/nsIconChannel.cpp@ac0c01689b40 (annotated)

image/decoders/icon/gtk/nsIconChannel.cpp@ac0c01689b40 (annotated)

image/decoders/icon/gtk/nsIconChannel.cpp

Thu, 15 Jan 2015 15:59:08 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 15 Jan 2015 15:59:08 +0100
branch: TOR_BUG_9701
changeset 10: ac0c01689b40
permissions: -rw-r--r--

Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* vim:set ts=2 sw=2 sts=2 cin et: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include <stdlib.h>
 #include <unistd.h>
 #include "mozilla/DebugOnly.h"
 #include "mozilla/Endian.h"
 #include <algorithm>
 #ifdef MOZ_ENABLE_GNOMEUI
 // Older versions of these headers seem to be missing an extern "C"
 extern "C" {
 #include <libgnome/libgnome.h>
 #include <libgnomeui/gnome-icon-theme.h>
 #include <libgnomeui/gnome-icon-lookup.h>
 #include <libgnomevfs/gnome-vfs-file-info.h>
 #include <libgnomevfs/gnome-vfs-ops.h>
 }
 #endif
 #ifdef MOZ_ENABLE_GIO
 #include <gio/gio.h>
 #endif
 #include <gtk/gtk.h>
 #include "nsMimeTypes.h"
 #include "nsIMIMEService.h"
 #include "nsIStringBundle.h"
 #include "nsNetUtil.h"
 #include "nsIURL.h"
 #include "prlink.h"
 #include "nsIconChannel.h"
 NS_IMPL_ISUPPORTS(nsIconChannel,
                   nsIRequest,
                   nsIChannel)
 #ifdef MOZ_ENABLE_GNOMEUI
 // These let us have a soft dependency on libgnomeui rather than a hard one. These are just basically the prototypes
 // of the functions in the libraries.
 typedef char* (*_GnomeIconLookup_fn)(GtkIconTheme *icon_theme, GnomeThumbnailFactory *thumbnail_factory,
                                      const char *file_uri, const char *custom_icon, GnomeVFSFileInfo *file_info,
                                      const char *mime_type, GnomeIconLookupFlags flags, GnomeIconLookupResultFlags *result);
 typedef GnomeIconTheme* (*_GnomeIconThemeNew_fn)(void);
 typedef int (*_GnomeInit_fn)(const char *app_id, const char *app_version, int argc, char **argv, const struct poptOption *options,
                              int flags, poptContext *return_ctx);
 typedef GnomeProgram* (*_GnomeProgramGet_fn)(void);
 typedef GnomeVFSResult (*_GnomeVFSGetFileInfo_fn)(const gchar *text_uri, GnomeVFSFileInfo *info, GnomeVFSFileInfoOptions options);
 typedef void (*_GnomeVFSFileInfoClear_fn)(GnomeVFSFileInfo *info);
 static PRLibrary* gLibGnomeUI = nullptr;
 static PRLibrary* gLibGnome = nullptr;
 static PRLibrary* gLibGnomeVFS = nullptr;
 static bool gTriedToLoadGnomeLibs = false;
 static _GnomeIconLookup_fn _gnome_icon_lookup = nullptr;
 static _GnomeIconThemeNew_fn _gnome_icon_theme_new = nullptr;
 static _GnomeInit_fn _gnome_init = nullptr;
 static _GnomeProgramGet_fn _gnome_program_get = nullptr;
 static _GnomeVFSGetFileInfo_fn _gnome_vfs_get_file_info = nullptr;
 static _GnomeVFSFileInfoClear_fn _gnome_vfs_file_info_clear = nullptr;
 #endif //MOZ_ENABLE_GNOMEUI
 static nsresult
 moz_gdk_pixbuf_to_channel(GdkPixbuf* aPixbuf, nsIURI *aURI,
                           nsIChannel **aChannel)
 {
   int width = gdk_pixbuf_get_width(aPixbuf);
   int height = gdk_pixbuf_get_height(aPixbuf);
   NS_ENSURE_TRUE(height < 256 && width < 256 && height > 0 && width > 0 &&
                  gdk_pixbuf_get_colorspace(aPixbuf) == GDK_COLORSPACE_RGB &&
                  gdk_pixbuf_get_bits_per_sample(aPixbuf) == 8 &&
                  gdk_pixbuf_get_has_alpha(aPixbuf) &&
                  gdk_pixbuf_get_n_channels(aPixbuf) == 4,
                  NS_ERROR_UNEXPECTED);
   const int n_channels = 4;
   gsize buf_size = 2 + n_channels * height * width;
   uint8_t * const buf = (uint8_t*)NS_Alloc(buf_size);
   NS_ENSURE_TRUE(buf, NS_ERROR_OUT_OF_MEMORY);
   uint8_t *out = buf;
   *(out++) = width;
   *(out++) = height;
   const guchar * const pixels = gdk_pixbuf_get_pixels(aPixbuf);
   int rowextra = gdk_pixbuf_get_rowstride(aPixbuf) - width * n_channels;
   // encode the RGB data and the A data
   const guchar * in = pixels;
   for (int y = 0; y < height; ++y, in += rowextra) {
     for (int x = 0; x < width; ++x) {
       uint8_t r = *(in++);
       uint8_t g = *(in++);
       uint8_t b = *(in++);
       uint8_t a = *(in++);
 #define DO_PREMULTIPLY(c_) uint8_t(uint16_t(c_) * uint16_t(a) / uint16_t(255))
 #if MOZ_LITTLE_ENDIAN
       *(out++) = DO_PREMULTIPLY(b);
       *(out++) = DO_PREMULTIPLY(g);
       *(out++) = DO_PREMULTIPLY(r);
       *(out++) = a;
 #else
       *(out++) = a;
       *(out++) = DO_PREMULTIPLY(r);
       *(out++) = DO_PREMULTIPLY(g);
       *(out++) = DO_PREMULTIPLY(b);
 #endif
 #undef DO_PREMULTIPLY
     }
   }
   NS_ASSERTION(out == buf + buf_size, "size miscalculation");
   nsresult rv;
   nsCOMPtr<nsIStringInputStream> stream =
     do_CreateInstance("@mozilla.org/io/string-input-stream;1", &rv);
   NS_ENSURE_SUCCESS(rv, rv);
   rv = stream->AdoptData((char*)buf, buf_size);
   NS_ENSURE_SUCCESS(rv, rv);
   rv = NS_NewInputStreamChannel(aChannel, aURI, stream,
                                 NS_LITERAL_CSTRING(IMAGE_ICON_MS));
   return rv;
 }
 static GtkWidget *gProtoWindow = nullptr;
 static GtkWidget *gStockImageWidget = nullptr;
 #ifdef MOZ_ENABLE_GNOMEUI
 static GnomeIconTheme *gIconTheme = nullptr;
 #endif //MOZ_ENABLE_GNOMEUI
 static void
 ensure_stock_image_widget()
 {
   // Only the style of the GtkImage needs to be used, but the widget is kept
   // to track dynamic style changes.
   if (!gProtoWindow) {
     gProtoWindow = gtk_window_new(GTK_WINDOW_POPUP);
     GtkWidget* protoLayout = gtk_fixed_new();
     gtk_container_add(GTK_CONTAINER(gProtoWindow), protoLayout);
     gStockImageWidget = gtk_image_new();
     gtk_container_add(GTK_CONTAINER(protoLayout), gStockImageWidget);
     gtk_widget_ensure_style(gStockImageWidget);
   }
 }
 #ifdef MOZ_ENABLE_GNOMEUI
 static nsresult
 ensure_libgnomeui()
 {
   // Attempt to get the libgnomeui symbol references. We do it this way so that stock icons from Init()
   // don't get held back by InitWithGnome()'s libgnomeui dependency.
   if (!gTriedToLoadGnomeLibs) {
     gLibGnomeUI = PR_LoadLibrary("libgnomeui-2.so.0");
     if (!gLibGnomeUI)
       return NS_ERROR_NOT_AVAILABLE;
     _gnome_init = (_GnomeInit_fn)PR_FindFunctionSymbol(gLibGnomeUI, "gnome_init_with_popt_table");
     _gnome_icon_theme_new = (_GnomeIconThemeNew_fn)PR_FindFunctionSymbol(gLibGnomeUI, "gnome_icon_theme_new");
     _gnome_icon_lookup = (_GnomeIconLookup_fn)PR_FindFunctionSymbol(gLibGnomeUI, "gnome_icon_lookup");
     if (!_gnome_init || !_gnome_icon_theme_new || !_gnome_icon_lookup) {
       PR_UnloadLibrary(gLibGnomeUI);
       gLibGnomeUI = nullptr;
       return NS_ERROR_NOT_AVAILABLE;
     }
   }
   if (!gLibGnomeUI)
     return NS_ERROR_NOT_AVAILABLE;
   return NS_OK;
 }
 static nsresult
 ensure_libgnome()
 {
   if (!gTriedToLoadGnomeLibs) {
     gLibGnome = PR_LoadLibrary("libgnome-2.so.0");
     if (!gLibGnome)
       return NS_ERROR_NOT_AVAILABLE;
     _gnome_program_get = (_GnomeProgramGet_fn)PR_FindFunctionSymbol(gLibGnome, "gnome_program_get");
     if (!_gnome_program_get) {
       PR_UnloadLibrary(gLibGnome);
       gLibGnome = nullptr;
       return NS_ERROR_NOT_AVAILABLE;
     }
   }
   if (!gLibGnome)
     return NS_ERROR_NOT_AVAILABLE;
   return NS_OK;
 }
 static nsresult
 ensure_libgnomevfs()
 {
   if (!gTriedToLoadGnomeLibs) {
     gLibGnomeVFS = PR_LoadLibrary("libgnomevfs-2.so.0");
     if (!gLibGnomeVFS)
       return NS_ERROR_NOT_AVAILABLE;
     _gnome_vfs_get_file_info = (_GnomeVFSGetFileInfo_fn)PR_FindFunctionSymbol(gLibGnomeVFS, "gnome_vfs_get_file_info");
     _gnome_vfs_file_info_clear = (_GnomeVFSFileInfoClear_fn)PR_FindFunctionSymbol(gLibGnomeVFS, "gnome_vfs_file_info_clear");
     if (!_gnome_vfs_get_file_info || !_gnome_vfs_file_info_clear) {
       PR_UnloadLibrary(gLibGnomeVFS);
       gLibGnomeVFS = nullptr;
       return NS_ERROR_NOT_AVAILABLE;
     }
   }
   if (!gLibGnomeVFS)
     return NS_ERROR_NOT_AVAILABLE;
   return NS_OK;
 }
 #endif //MOZ_ENABLE_GNOMEUI
 static GtkIconSize
 moz_gtk_icon_size(const char *name)
 {
   if (strcmp(name, "button") == 0)
     return GTK_ICON_SIZE_BUTTON;
   if (strcmp(name, "menu") == 0)
     return GTK_ICON_SIZE_MENU;
   if (strcmp(name, "toolbar") == 0)
     return GTK_ICON_SIZE_LARGE_TOOLBAR;
   if (strcmp(name, "toolbarsmall") == 0)
     return GTK_ICON_SIZE_SMALL_TOOLBAR;
   if (strcmp(name, "dnd") == 0)
     return GTK_ICON_SIZE_DND;
   if (strcmp(name, "dialog") == 0)
     return GTK_ICON_SIZE_DIALOG;
   return GTK_ICON_SIZE_MENU;
 }
 #if defined(MOZ_ENABLE_GNOMEUI) || defined(MOZ_ENABLE_GIO)
 static int32_t
 GetIconSize(nsIMozIconURI *aIconURI)
 {
   nsAutoCString iconSizeString;
   aIconURI->GetIconSize(iconSizeString);
   if (iconSizeString.IsEmpty()) {
     uint32_t size;
     mozilla::DebugOnly<nsresult> rv = aIconURI->GetImageSize(&size);
     NS_ASSERTION(NS_SUCCEEDED(rv), "GetImageSize failed");
     return size;
   } else {
     int size;
     GtkIconSize icon_size = moz_gtk_icon_size(iconSizeString.get());
     gtk_icon_size_lookup(icon_size, &size, nullptr);
     return size;
   }
 }
 /* Scale icon buffer to preferred size */
 static nsresult
 ScaleIconBuf(GdkPixbuf **aBuf, int32_t iconSize)
 {
   // Scale buffer only if width or height differ from preferred size
   if (gdk_pixbuf_get_width(*aBuf)  != iconSize &&
       gdk_pixbuf_get_height(*aBuf) != iconSize) {
     GdkPixbuf *scaled = gdk_pixbuf_scale_simple(*aBuf, iconSize, iconSize,
                                                 GDK_INTERP_BILINEAR);
     // replace original buffer by scaled
     g_object_unref(*aBuf);
     *aBuf = scaled;
     if (!scaled)
       return NS_ERROR_OUT_OF_MEMORY;
   }
   return NS_OK;
 }
 #endif
 #ifdef MOZ_ENABLE_GNOMEUI
 nsresult
 nsIconChannel::InitWithGnome(nsIMozIconURI *aIconURI)
 {
   nsresult rv;
   if (NS_FAILED(ensure_libgnomeui()) || NS_FAILED(ensure_libgnome()) || NS_FAILED(ensure_libgnomevfs())) {
     gTriedToLoadGnomeLibs = true;
     return NS_ERROR_NOT_AVAILABLE;
   }
   gTriedToLoadGnomeLibs = true;
   if (!_gnome_program_get()) {
     // Get the brandShortName from the string bundle to pass to GNOME
     // as the application name.  This may be used for things such as
     // the title of grouped windows in the panel.
     nsCOMPtr<nsIStringBundleService> bundleService =
       do_GetService(NS_STRINGBUNDLE_CONTRACTID);
     NS_ASSERTION(bundleService, "String bundle service must be present!");
     nsCOMPtr<nsIStringBundle> bundle;
     bundleService->CreateBundle("chrome://branding/locale/brand.properties",
                                 getter_AddRefs(bundle));
     nsAutoString appName;
     if (bundle) {
       bundle->GetStringFromName(MOZ_UTF16("brandShortName"),
                                 getter_Copies(appName));
     } else {
       NS_WARNING("brand.properties not present, using default application name");
       appName.Assign(NS_LITERAL_STRING("Gecko"));
     }
     char* empty[] = { "" };
     _gnome_init(NS_ConvertUTF16toUTF8(appName).get(),
                 "1.0", 1, empty, nullptr, 0, nullptr);
   }
   uint32_t iconSize = GetIconSize(aIconURI);
   nsAutoCString type;
   aIconURI->GetContentType(type);
   GnomeVFSFileInfo fileInfo = {0};
   fileInfo.refcount = 1; // In case some GnomeVFS function addrefs and releases it
   nsAutoCString spec;
   nsCOMPtr<nsIURL> url;
   rv = aIconURI->GetIconURL(getter_AddRefs(url));
   if (url) {
     url->GetAsciiSpec(spec);
     // Only ask gnome-vfs for a GnomeVFSFileInfo for file: uris, to avoid a
     // network request
     bool isFile;
     if (NS_SUCCEEDED(url->SchemeIs("file", &isFile)) && isFile) {
       _gnome_vfs_get_file_info(spec.get(), &fileInfo, GNOME_VFS_FILE_INFO_DEFAULT);
     }
     else {
       // The filename we get is UTF-8-compatible, which matches gnome expectations.
       // See also: http://lists.gnome.org/archives/gnome-vfs-list/2004-March/msg00049.html
       // "Whenever we can detect the charset used for the URI type we try to
       //  convert it to/from utf8 automatically inside gnome-vfs."
       // I'll interpret that as "otherwise, this field is random junk".
       nsAutoCString name;
       url->GetFileName(name);
       fileInfo.name = g_strdup(name.get());
       if (!type.IsEmpty()) {
         fileInfo.valid_fields = GNOME_VFS_FILE_INFO_FIELDS_MIME_TYPE;
         fileInfo.mime_type = g_strdup(type.get());
       }
     }
   }
   if (type.IsEmpty()) {
     nsCOMPtr<nsIMIMEService> ms(do_GetService("@mozilla.org/mime;1"));
     if (ms) {
       nsAutoCString fileExt;
       aIconURI->GetFileExtension(fileExt);
       if (!fileExt.IsEmpty()) {
         ms->GetTypeFromExtension(fileExt, type);
       }
     }
   }
   // Get the icon theme
   if (!gIconTheme) {
     gIconTheme = _gnome_icon_theme_new();
     if (!gIconTheme) {
       _gnome_vfs_file_info_clear(&fileInfo);
       return NS_ERROR_NOT_AVAILABLE;
     }
   }
   char* name = _gnome_icon_lookup(gIconTheme, nullptr, spec.get(), nullptr,
                                   &fileInfo, type.get(),
                                   GNOME_ICON_LOOKUP_FLAGS_NONE, nullptr);
   _gnome_vfs_file_info_clear(&fileInfo);
   if (!name)
     return NS_ERROR_NOT_AVAILABLE;
   // Get the default theme associated with the screen
   // Do NOT free.
   GtkIconTheme *theme = gtk_icon_theme_get_default();
   if (!theme) {
     g_free(name);
     return NS_ERROR_UNEXPECTED;
   }
   GError *err = nullptr;
   GdkPixbuf* buf = gtk_icon_theme_load_icon(theme, name, iconSize, (GtkIconLookupFlags)0, &err);
   g_free(name);
   if (!buf) {
     if (err)
       g_error_free(err);
     return NS_ERROR_UNEXPECTED;
   }
   rv = ScaleIconBuf(&buf, iconSize);
   NS_ENSURE_SUCCESS(rv, rv);
   rv = moz_gdk_pixbuf_to_channel(buf, aIconURI,
                                  getter_AddRefs(mRealChannel));
   g_object_unref(buf);
   return rv;
 }
 #endif // MOZ_ENABLE_GNOMEUI
 #ifdef MOZ_ENABLE_GIO
 nsresult
 nsIconChannel::InitWithGIO(nsIMozIconURI *aIconURI)
 {
   GIcon *icon = nullptr;
   nsCOMPtr<nsIURL> fileURI;
   // Read icon content
   aIconURI->GetIconURL(getter_AddRefs(fileURI));
   // Get icon for file specified by URI
   if (fileURI) {
     bool isFile;
     nsAutoCString spec;
     fileURI->GetAsciiSpec(spec);
     if (NS_SUCCEEDED(fileURI->SchemeIs("file", &isFile)) && isFile) {
       GFile *file = g_file_new_for_uri(spec.get());
       GFileInfo *fileInfo = g_file_query_info(file,
                                               G_FILE_ATTRIBUTE_STANDARD_ICON,
                                               G_FILE_QUERY_INFO_NONE,
                                               nullptr, nullptr);
       g_object_unref(file);
       if (fileInfo) {
         // icon from g_content_type_get_icon doesn't need unref
         icon = g_file_info_get_icon(fileInfo);
         if (icon)
           g_object_ref(icon);
         g_object_unref(fileInfo);
       }
     }
   }
   // Try to get icon by using MIME type
   if (!icon) {
     nsAutoCString type;
     aIconURI->GetContentType(type);
     // Try to get MIME type from file extension by using nsIMIMEService
     if (type.IsEmpty()) {
       nsCOMPtr<nsIMIMEService> ms(do_GetService("@mozilla.org/mime;1"));
       if (ms) {
         nsAutoCString fileExt;
         aIconURI->GetFileExtension(fileExt);
         ms->GetTypeFromExtension(fileExt, type);
       }
     }
     char *ctype = nullptr; // character representation of content type
     if (!type.IsEmpty()) {
       ctype = g_content_type_from_mime_type(type.get());
     }
     if (ctype) {
       icon = g_content_type_get_icon(ctype);
       g_free(ctype);
     }
   }
   // Get default icon theme
   GtkIconTheme *iconTheme = gtk_icon_theme_get_default();
   GtkIconInfo *iconInfo = nullptr;
   // Get icon size
   int32_t iconSize = GetIconSize(aIconURI);
   if (icon) {
     // Use icon and theme to get GtkIconInfo
     iconInfo = gtk_icon_theme_lookup_by_gicon(iconTheme,
                                               icon, iconSize,
                                               (GtkIconLookupFlags)0);
     g_object_unref(icon);
   }
   if (!iconInfo) {
     // Mozilla's mimetype lookup failed. Try the "unknown" icon.
     iconInfo = gtk_icon_theme_lookup_icon(iconTheme,
                                           "unknown", iconSize,
                                           (GtkIconLookupFlags)0);
     if (!iconInfo) {
       return NS_ERROR_NOT_AVAILABLE;
     }
   }
   // Create a GdkPixbuf buffer containing icon and scale it
   GdkPixbuf* buf = gtk_icon_info_load_icon(iconInfo, nullptr);
   gtk_icon_info_free(iconInfo);
   if (!buf) {
     return NS_ERROR_UNEXPECTED;
   }
   nsresult rv = ScaleIconBuf(&buf, iconSize);
   NS_ENSURE_SUCCESS(rv, rv);
   rv = moz_gdk_pixbuf_to_channel(buf, aIconURI,
                                  getter_AddRefs(mRealChannel));
   g_object_unref(buf);
   return rv;
 }
 #endif // MOZ_ENABLE_GIO
 nsresult
 nsIconChannel::Init(nsIURI* aURI)
 {
   nsCOMPtr<nsIMozIconURI> iconURI = do_QueryInterface(aURI);
   NS_ASSERTION(iconURI, "URI is not an nsIMozIconURI");
   nsAutoCString stockIcon;
   iconURI->GetStockIcon(stockIcon);
   if (stockIcon.IsEmpty()) {
 #ifdef MOZ_ENABLE_GNOMEUI
     return InitWithGnome(iconURI);
 #else
 #ifdef MOZ_ENABLE_GIO
     return InitWithGIO(iconURI);
 #else
     return NS_ERROR_NOT_AVAILABLE;
 #endif
 #endif
   }
   // Search for stockIcon
   nsAutoCString iconSizeString;
   iconURI->GetIconSize(iconSizeString);
   nsAutoCString iconStateString;
   iconURI->GetIconState(iconStateString);
   GtkIconSize icon_size = moz_gtk_icon_size(iconSizeString.get());
   GtkStateType state = iconStateString.EqualsLiteral("disabled") ?
     GTK_STATE_INSENSITIVE : GTK_STATE_NORMAL;
   // First lookup the icon by stock id and text direction.
   GtkTextDirection direction = GTK_TEXT_DIR_NONE;
   if (StringEndsWith(stockIcon, NS_LITERAL_CSTRING("-ltr"))) {
     direction = GTK_TEXT_DIR_LTR;
   } else if (StringEndsWith(stockIcon, NS_LITERAL_CSTRING("-rtl"))) {
     direction = GTK_TEXT_DIR_RTL;
   }
   bool forceDirection = direction != GTK_TEXT_DIR_NONE;
   nsAutoCString stockID;
   bool useIconName = false;
   if (!forceDirection) {
     direction = gtk_widget_get_default_direction();
     stockID = stockIcon;
   } else {
     // GTK versions < 2.22 use icon names from concatenating stock id with
     // -(rtl|ltr), which is how the moz-icon stock name is interpreted here.
     stockID = Substring(stockIcon, 0, stockIcon.Length() - 4);
     // However, if we lookup bidi icons by the stock name, then GTK versions
     // >= 2.22 will use a bidi lookup convention that most icon themes do not
     // yet follow.  Therefore, we first check to see if the theme supports the
     // old icon name as this will have bidi support (if found).
     GtkIconTheme *icon_theme = gtk_icon_theme_get_default();
     // Micking what gtk_icon_set_render_icon does with sizes, though it's not
     // critical as icons will be scaled to suit size.  It just means we follow
     // the same pathes and so share caches.
     gint width, height;
     if (gtk_icon_size_lookup(icon_size, &width, &height)) {
       gint size = std::min(width, height);
       // We use gtk_icon_theme_lookup_icon() without
       // GTK_ICON_LOOKUP_USE_BUILTIN instead of gtk_icon_theme_has_icon() so
       // we don't pick up fallback icons added by distributions for backward
       // compatibility.
       GtkIconInfo *icon =
         gtk_icon_theme_lookup_icon(icon_theme, stockIcon.get(),
                                    size, (GtkIconLookupFlags)0);
       if (icon) {
         useIconName = true;
         gtk_icon_info_free(icon);
       }
     }
   }
   ensure_stock_image_widget();
   GtkStyle *style = gtk_widget_get_style(gStockImageWidget);
   GtkIconSet *icon_set = nullptr;
   if (!useIconName) {
     icon_set = gtk_style_lookup_icon_set(style, stockID.get());
   }
   if (!icon_set) {
     // Either we have choosen icon-name lookup for a bidi icon, or stockIcon is
     // not a stock id so we assume it is an icon name.
     useIconName = true;
     // Creating a GtkIconSet is a convenient way to allow the style to
     // render the icon, possibly with variations suitable for insensitive
     // states.
     icon_set = gtk_icon_set_new();
     GtkIconSource *icon_source = gtk_icon_source_new();
     gtk_icon_source_set_icon_name(icon_source, stockIcon.get());
     gtk_icon_set_add_source(icon_set, icon_source);
     gtk_icon_source_free(icon_source);
   }
   GdkPixbuf *icon =
     gtk_icon_set_render_icon(icon_set, style, direction, state,
                              icon_size, gStockImageWidget, nullptr);
   if (useIconName) {
     gtk_icon_set_unref(icon_set);
   }
   // According to documentation, gtk_icon_set_render_icon() never returns
   // nullptr, but it does return nullptr when we have the problem reported
   // here: https://bugzilla.gnome.org/show_bug.cgi?id=629878#c13
   if (!icon)
     return NS_ERROR_NOT_AVAILABLE;
   nsresult rv = moz_gdk_pixbuf_to_channel(icon, iconURI,
                                           getter_AddRefs(mRealChannel));
   g_object_unref(icon);
   return rv;
 }
 void
 nsIconChannel::Shutdown() {
   if (gProtoWindow) {
     gtk_widget_destroy(gProtoWindow);
     gProtoWindow = nullptr;
     gStockImageWidget = nullptr;
   }
 #ifdef MOZ_ENABLE_GNOMEUI
   if (gIconTheme) {
     g_object_unref(G_OBJECT(gIconTheme));
     gIconTheme = nullptr;
   }
   gTriedToLoadGnomeLibs = false;
   if (gLibGnomeUI) {
     PR_UnloadLibrary(gLibGnomeUI);
     gLibGnomeUI = nullptr;
   }
   if (gLibGnome) {
     PR_UnloadLibrary(gLibGnome);
     gLibGnome = nullptr;
   }
   if (gLibGnomeVFS) {
     PR_UnloadLibrary(gLibGnomeVFS);
     gLibGnomeVFS = nullptr;
   }
 #endif //MOZ_ENABLE_GNOMEUI
 }

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image/decoders/icon/gtk/nsIconChannel.cpp@ac0c01689b40 (annotated)

image/decoders/icon/gtk/nsIconChannel.cpp