Refactor JPEG decoding into decodeJPEGIntoSurface

src/Image.cc

@@ -12,11 +12,6 @@
 #include <errno.h>
 #include <node_buffer.h>
 
-#ifdef HAVE_JPEG
-#include <jpeglib.h>
-#include <jerror.h>
-#endif
-
 #ifdef HAVE_GIF
 #include <gif_lib.h>
 typedef struct {
@@ -601,45 +596,28 @@ static void jpeg_mem_src (j_decompress_ptr cinfo, void* buffer, long nbytes) {
 
 #endif
 
-/*
- * Load jpeg from buffer.
- */
-
 cairo_status_t
-Image::loadJPEGFromBuffer(uint8_t *buf, unsigned len) {
-  // TODO: remove this duplicate logic
-  // JPEG setup
-  struct jpeg_decompress_struct info;
-  struct jpeg_error_mgr err;
-  info.err = jpeg_std_error(&err);
-  jpeg_create_decompress(&info);
-  jpeg_mem_src(&info, buf, len);
-  jpeg_read_header(&info, 1);
-  jpeg_start_decompress(&info);
-  width = info.output_width;
-  height = info.output_height;
-
-  // Data alloc
+Image::decodeJPEGIntoSurface(jpeg_decompress_struct *info) {
   int stride = width * 4;
-  uint8_t *data = (uint8_t *) malloc(width * height * 4);
+  cairo_status_t status;
 
+  uint8_t *data = (uint8_t *) malloc(width * height * 4);
   if (!data) {
-    jpeg_finish_decompress(&info);
-    jpeg_destroy_decompress(&info);
+    jpeg_finish_decompress(info);
+    jpeg_destroy_decompress(info);
     return CAIRO_STATUS_NO_MEMORY;
   }
-  
+
   uint8_t *src = (uint8_t *) malloc(width * 3);
   if (!src) {
     free(data);
-    jpeg_finish_decompress(&info);
-    jpeg_destroy_decompress(&info);
+    jpeg_finish_decompress(info);
+    jpeg_destroy_decompress(info);
     return CAIRO_STATUS_NO_MEMORY;
   }
 
-  // Copy RGB -> ARGB
   for (int y = 0; y < height; ++y) {
-    jpeg_read_scanlines(&info, &src, 1);
+    jpeg_read_scanlines(info, &src, 1);
     uint32_t *row = (uint32_t *)(data + stride * y);
     for (int x = 0; x < width; ++x) {
       int bx = 3 * x;
@@ -651,7 +629,6 @@ Image::loadJPEGFromBuffer(uint8_t *buf, unsigned len) {
     }
   }
 
-  // New image surface
   _surface = cairo_image_surface_create_for_data(
       data
     , CAIRO_FORMAT_ARGB32
@@ -659,94 +636,69 @@ Image::loadJPEGFromBuffer(uint8_t *buf, unsigned len) {
     , height
     , cairo_format_stride_for_width(CAIRO_FORMAT_ARGB32, width));
 
-  // Cleanup
-  free(src);
-  jpeg_finish_decompress(&info);
-  jpeg_destroy_decompress(&info);
-  cairo_status_t status = cairo_surface_status(_surface);
+  jpeg_finish_decompress(info);
+  jpeg_destroy_decompress(info);
+  status = cairo_surface_status(_surface);
 
   if (status) {
     free(data);
+    free(src);
     return status;
   }
 
+  free(src);
   _data = data;
   return CAIRO_STATUS_SUCCESS;
 }
 
 /*
- * Load JPEG, convert RGB to ARGB.
+ * Load jpeg from buffer.
  */
 
 cairo_status_t
-Image::loadJPEG(FILE *stream) {
+Image::loadJPEGFromBuffer(uint8_t *buf, unsigned len) {
+  // TODO: remove this duplicate logic
   // JPEG setup
   struct jpeg_decompress_struct info;
   struct jpeg_error_mgr err;
   info.err = jpeg_std_error(&err);
   jpeg_create_decompress(&info);
-  jpeg_stdio_src(&info, stream);
+
+  jpeg_mem_src(&info, buf, len);
+
   jpeg_read_header(&info, 1);
   jpeg_start_decompress(&info);
   width = info.output_width;
   height = info.output_height;
 
-  // Data alloc
-  int stride = width * 4;
-  uint8_t *data = (uint8_t *) malloc(width * height * 4);
+  return decodeJPEGIntoSurface(&info);
+}
 
-  if (!data) {
-    fclose(stream);
-    jpeg_finish_decompress(&info);
-    jpeg_destroy_decompress(&info);
-    return CAIRO_STATUS_NO_MEMORY;
-  }
+/*
+ * Load JPEG, convert RGB to ARGB.
+ */
 
-  uint8_t *src = (uint8_t *) malloc(width * 3);
+cairo_status_t
+Image::loadJPEG(FILE *stream) {
+  // JPEG setup
+  struct jpeg_decompress_struct info;
+  struct jpeg_error_mgr err;
+  info.err = jpeg_std_error(&err);
+  jpeg_create_decompress(&info);
 
-  if (!src) {
-    free(data);
-    fclose(stream);
-    jpeg_finish_decompress(&info);
-    jpeg_destroy_decompress(&info);
-    return CAIRO_STATUS_NO_MEMORY;
-  }
+  jpeg_stdio_src(&info, stream);
 
-  // Copy RGB -> ARGB
-  for (int y = 0; y < height; ++y) {
-    jpeg_read_scanlines(&info, &src, 1);
-    uint32_t *row = (uint32_t *)(data + stride * y);
-    for (int x = 0; x < width; ++x) {
-      int bx = 3 * x;
-      uint32_t *pixel = row + x;
-      *pixel = 255 << 24
-        | src[bx + 0] << 16
-        | src[bx + 1] << 8
-        | src[bx + 2];
-    }
-  }
+  jpeg_read_header(&info, 1);
+  jpeg_start_decompress(&info);
+  width = info.output_width;
+  height = info.output_height;
 
-  // New image surface
-  _surface = cairo_image_surface_create_for_data(
-      data
-    , CAIRO_FORMAT_ARGB32
-    , width
-    , height
-    , cairo_format_stride_for_width(CAIRO_FORMAT_ARGB32, width));
+  cairo_status_t status;
 
-  // Cleanup
-  free(src);
+  status = decodeJPEGIntoSurface(&info);
   fclose(stream);
-  jpeg_finish_decompress(&info);
-  jpeg_destroy_decompress(&info);
-  cairo_status_t status = cairo_surface_status(_surface);
 
-  if (status) {
-    free(data);
-    return status;
-  }
-
-  return CAIRO_STATUS_SUCCESS;
+  return status;
 }
 
 #endif /* HAVE_JPEG */

src/Image.h

@@ -10,6 +10,11 @@
 
 #include "Canvas.h"
 
+#ifdef HAVE_JPEG
+#include <jpeglib.h>
+#include <jerror.h>
+#endif
+
 class Image: public node::ObjectWrap {
   public:
     char *filename;
@@ -47,6 +52,7 @@ class Image: public node::ObjectWrap {
 #ifdef HAVE_JPEG
     cairo_status_t loadJPEGFromBuffer(uint8_t *buf, unsigned len);
     cairo_status_t loadJPEG(FILE *stream);
+    cairo_status_t decodeJPEGIntoSurface(jpeg_decompress_struct *info);
 #endif
     void error(Local<Value> error);
     void loaded();
@@ -59,6 +65,12 @@ class Image: public node::ObjectWrap {
       , COMPLETE
     } state;
 
+    enum {
+      DATA_IMAGE,
+      DATA_MIME,
+      DATA_IMAGE_AND_MIME
+    } data_mode;
+
     typedef enum {
         UNKNOWN
       , GIF