[gthumb] jpeg loader: cancel the image loading faster

[Paolo Bacchilega <paobac src gnome org>]

commit 69fe61d039512965faf1c1439af11e9aed392fcb
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Fri Jun 28 16:52:10 2013 +0200

    jpeg loader: cancel the image loading faster
    
    added other points where the cancellable is checked

 extensions/cairo_io/cairo-image-surface-jpeg.c |   68 +++++++++++++++---------
 1 files changed, 42 insertions(+), 26 deletions(-)
---
diff --git a/extensions/cairo_io/cairo-image-surface-jpeg.c b/extensions/cairo_io/cairo-image-surface-jpeg.c
index b8ee828..54985fb 100644
--- a/extensions/cairo_io/cairo-image-surface-jpeg.c
+++ b/extensions/cairo_io/cairo-image-surface-jpeg.c
@@ -273,7 +273,7 @@ _cairo_image_surface_create_from_jpeg (GInputStream  *istream,
 
                        while (srcinfo.output_scanline < srcinfo.output_height) {
                                if (g_cancellable_is_cancelled (cancellable))
-                                       break;
+                                       goto stop_loading;
 
                                n_lines = jpeg_read_scanlines (&srcinfo, buffer, srcinfo.rec_outbuf_height);
 
@@ -282,6 +282,9 @@ _cairo_image_surface_create_from_jpeg (GInputStream  *istream,
                                        p_surface = surface_row;
                                        p_buffer = buffer_row[l];
 
+                                       if (g_cancellable_is_cancelled (cancellable))
+                                               goto stop_loading;
+
                                        for (x = 0; x < srcinfo.output_width; x++) {
                                                if (srcinfo.saw_Adobe_marker) {
                                                        c = p_buffer[0];
@@ -318,7 +321,7 @@ _cairo_image_surface_create_from_jpeg (GInputStream  *istream,
                {
                        while (srcinfo.output_scanline < srcinfo.output_height) {
                                if (g_cancellable_is_cancelled (cancellable))
-                                       break;
+                                       goto stop_loading;
 
                                n_lines = jpeg_read_scanlines (&srcinfo, buffer, srcinfo.rec_outbuf_height);
 
@@ -327,6 +330,9 @@ _cairo_image_surface_create_from_jpeg (GInputStream  *istream,
                                        p_surface = surface_row;
                                        p_buffer = buffer_row[l];
 
+                                       if (g_cancellable_is_cancelled (cancellable))
+                                               goto stop_loading;
+
                                        for (x = 0; x < srcinfo.output_width; x++) {
                                                r = g = b = p_buffer[0];
                                                pixel = CAIRO_RGBA_TO_UINT32 (r, g, b, 0xff);
@@ -347,7 +353,7 @@ _cairo_image_surface_create_from_jpeg (GInputStream  *istream,
                {
                        while (srcinfo.output_scanline < srcinfo.output_height) {
                                if (g_cancellable_is_cancelled (cancellable))
-                                       break;
+                                       goto stop_loading;
 
                                n_lines = jpeg_read_scanlines (&srcinfo, buffer, srcinfo.rec_outbuf_height);
 
@@ -356,6 +362,9 @@ _cairo_image_surface_create_from_jpeg (GInputStream  *istream,
                                        p_surface = surface_row;
                                        p_buffer = buffer_row[l];
 
+                                       if (g_cancellable_is_cancelled (cancellable))
+                                               goto stop_loading;
+
                                        for (x = 0; x < srcinfo.output_width; x++) {
                                                r = p_buffer[0];
                                                g = p_buffer[1];
@@ -391,7 +400,7 @@ _cairo_image_surface_create_from_jpeg (GInputStream  *istream,
 
                        while (srcinfo.output_scanline < srcinfo.output_height) {
                                if (g_cancellable_is_cancelled (cancellable))
-                                       break;
+                                       goto stop_loading;
 
                                n_lines = jpeg_read_scanlines (&srcinfo, buffer, srcinfo.rec_outbuf_height);
 
@@ -400,6 +409,9 @@ _cairo_image_surface_create_from_jpeg (GInputStream  *istream,
                                        p_surface = surface_row;
                                        p_buffer = buffer_row[l];
 
+                                       if (g_cancellable_is_cancelled (cancellable))
+                                               goto stop_loading;
+
                                        for (x = 0; x < srcinfo.output_width; x++) {
                                                Y = p_buffer[0];
                                                Cb = p_buffer[1];
@@ -443,7 +455,7 @@ _cairo_image_surface_create_from_jpeg (GInputStream  *istream,
 
                        while (srcinfo.output_scanline < srcinfo.output_height) {
                                if (g_cancellable_is_cancelled (cancellable))
-                                       break;
+                                       goto stop_loading;
 
                                n_lines = jpeg_read_scanlines (&srcinfo, buffer, srcinfo.rec_outbuf_height);
 
@@ -452,6 +464,9 @@ _cairo_image_surface_create_from_jpeg (GInputStream  *istream,
                                        p_surface = surface_row;
                                        p_buffer = buffer_row[l];
 
+                                       if (g_cancellable_is_cancelled (cancellable))
+                                               goto stop_loading;
+
                                        for (x = 0; x < srcinfo.output_width; x++) {
                                                Y = p_buffer[0];
                                                Cb = p_buffer[1];
@@ -491,24 +506,11 @@ _cairo_image_surface_create_from_jpeg (GInputStream  *istream,
                break;
        }
 
-       if (! g_cancellable_is_cancelled (cancellable)) {
-               cairo_surface_mark_dirty (surface);
-
-               /* Scale to the requested size */
-
-               if (load_scaled) {
-                       cairo_surface_t *scaled;
-                       int              width;
-                       int              height;
+       stop_loading:
 
-                       width = destination_width;
-                       height = destination_height;
-                       scale_keeping_ratio (&width, &height, requested_size, requested_size, TRUE);
-                       scaled = _cairo_image_surface_scale (surface, width, height, SCALE_FILTER_BEST, NULL);
+       cairo_surface_mark_dirty (surface);
 
-                       cairo_surface_destroy (surface);
-                       surface = scaled;
-               }
+       if (! g_cancellable_is_cancelled (cancellable)) {
 
                /* Set the original dimensions */
 
@@ -528,18 +530,32 @@ _cairo_image_surface_create_from_jpeg (GInputStream  *istream,
                        if (original_height != NULL)
                                *original_height = srcinfo.image_height;
                }
+               jpeg_finish_decompress (&srcinfo);
+               jpeg_destroy_decompress (&srcinfo);
+
+               /* Scale to the requested size */
+
+               if (load_scaled) {
+                       cairo_surface_t *scaled;
+                       int              width;
+                       int              height;
+
+                       width = destination_width;
+                       height = destination_height;
+                       scale_keeping_ratio (&width, &height, requested_size, requested_size, TRUE);
+                       scaled = _cairo_image_surface_scale (surface, width, height, SCALE_FILTER_BEST, NULL);
+
+                       cairo_surface_destroy (surface);
+                       surface = scaled;
+               }
 
                /*_cairo_image_surface_set_attribute_int (surface, "Image::Rotation", rotation); FIXME*/
-
                /* FIXME _cairo_image_surface_set_attribute (surface, "Jpeg::ColorSpace", 
jpeg_color_space_name (srcinfo.jpeg_color_space)); */
 
                gth_image_set_cairo_surface (image, surface);
-
-               jpeg_finish_decompress (&srcinfo);
-               jpeg_destroy_decompress (&srcinfo);
        }
        else {
-               jpeg_destroy ((j_common_ptr) &srcinfo);
+               jpeg_destroy_decompress (&srcinfo);
                g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CANCELLED, "");
        }