GUAC-236: Assemble entire image data prior to decoding. Switch to simple decoder function (no struct).

src/guacenc/image-stream.c

@@ -30,14 +30,16 @@
 #include "webp.h"
 #endif
 
+#include <cairo/cairo.h>
+
 #include <stdlib.h>
 #include <string.h>
 
 guacenc_decoder_mapping guacenc_decoder_map[] = {
-    {"image/png",  &guacenc_png_decoder},
+    {"image/png",  guacenc_png_decoder},
-    {"image/jpeg", &guacenc_jpeg_decoder},
+    {"image/jpeg", guacenc_jpeg_decoder},
 #ifdef ENABLE_WEBP
-    {"image/webp", &guacenc_webp_decoder},
+    {"image/webp", guacenc_webp_decoder},
 #endif
     {NULL,         NULL}
 };
@@ -78,9 +80,12 @@ guacenc_image_stream* guacenc_image_stream_alloc(int mask, int index,
     stream->y = y;
 
     /* Associate with corresponding decoder */
-    guacenc_decoder* decoder = stream->decoder = guacenc_get_decoder(mimetype);
+    stream->decoder = guacenc_get_decoder(mimetype);
-    if (decoder != NULL)
+
-        decoder->init_handler(stream);
+    /* Allocate initial buffer */
+    stream->length = 0;
+    stream->max_length = GUACENC_IMAGE_STREAM_INITIAL_LENGTH;
+    stream->buffer = (unsigned char*) malloc(stream->max_length);
 
     return stream;
 
@@ -89,12 +94,27 @@ guacenc_image_stream* guacenc_image_stream_alloc(int mask, int index,
 int guacenc_image_stream_receive(guacenc_image_stream* stream,
         unsigned char* data, int length) {
 
-    /* Invoke data handler of corresponding decoder (if any) */
+    /* Allocate more space if necessary */
-    guacenc_decoder* decoder = stream->decoder;
+    if (stream->max_length - stream->length < length) {
-    if (decoder != NULL)
-        return decoder->data_handler(stream, data, length);
 
-    /* If there is no decoder, simply return success */
+        /* Calculate a reasonable new max length guaranteed to fit buffer */
+        int new_max_length = stream->max_length * 2 + length;
+
+        /* Attempt to resize buffer */
+        unsigned char* new_buffer =
+            (unsigned char*) realloc(stream->buffer, new_max_length);
+        if (new_buffer == NULL)
+            return 1;
+
+        /* Store updated buffer and size */
+        stream->buffer = new_buffer;
+        stream->max_length = new_max_length;
+
+    }
+
+    /* Append data */
+    memcpy(stream->buffer + stream->length, data, length);
+    stream->length += length;
     return 0;
 
 }
@@ -102,12 +122,20 @@ int guacenc_image_stream_receive(guacenc_image_stream* stream,
 int guacenc_image_stream_end(guacenc_image_stream* stream,
         guacenc_buffer* buffer) {
 
-    /* Invoke end handler of corresponding decoder (if any) */
-    guacenc_decoder* decoder = stream->decoder;
-    if (decoder != NULL)
-        return decoder->end_handler(stream, buffer);
-
     /* If there is no decoder, simply return success */
+    guacenc_decoder* decoder = stream->decoder;
+    if (decoder == NULL)
+        return 0;
+
+    /* Decode received data to a Cairo surface */
+    cairo_surface_t* surface = stream->decoder(stream->buffer, stream->length);
+    if (surface == NULL)
+        return 1;
+
+    /* Draw surface to buffer */
+    cairo_set_source_surface(buffer->cairo, surface, stream->x, stream->y);
+    cairo_fill(buffer->cairo);
+    cairo_surface_destroy(surface);
     return 0;
 
 }
@@ -118,10 +146,8 @@ int guacenc_image_stream_free(guacenc_image_stream* stream) {
     if (stream == NULL)
         return 0;
 
-    /* Invoke free handler for decoder (if associated) */
+    /* Free image buffer */
-    guacenc_decoder* decoder = stream->decoder;
+    free(stream->buffer);
-    if (decoder != NULL)
-        decoder->free_handler(stream);
 
     /* Free actual stream */
     free(stream);

src/guacenc/image-stream.h

@@ -26,11 +26,31 @@
 #include "config.h"
 #include "buffer.h"
 
+#include <cairo/cairo.h>
+
 /**
- * A decoder implementation which processes arbitrary image data of a
+ * The initial number of bytes to allocate for the image data buffer. If this
- * particular type. Image data is fed explicitly into the decoder as chunks.
+ * buffer is not sufficiently larged, it will be dynamically reallocated as it
+ * grows.
  */
-typedef struct guacenc_decoder guacenc_decoder;
+#define GUACENC_IMAGE_STREAM_INITIAL_LENGTH 4096
+
+/**
+ * Callback function which is provided raw, encoded image data of the given
+ * length. The function is expected to return a new Cairo surface which will
+ * later (by guacenc) be freed via cairo_surface_destroy().
+ *
+ * @param data
+ *     The raw encoded image data that this function must decode.
+ *
+ * @param length
+ *     The length of the image data, in bytes.
+ *
+ * @return
+ *     A newly-allocated Cairo surface containing the decoded image, or NULL
+ *     or decoding fails.
+ */
+typedef cairo_surface_t* guacenc_decoder(unsigned char* data, int length);
 
 /**
  * The current state of an allocated Guacamole image stream.
@@ -60,117 +80,34 @@ typedef struct guacenc_image_stream {
      */
     int y;
 
+    /**
+     * Buffer of image data which will be built up over time as chunks are
+     * received via "blob" instructions. This will ultimately be passed in its
+     * entirety to the decoder function.
+     */
+    unsigned char* buffer;
+
+    /**
+     * The number of bytes currently stored in the buffer.
+     */
+    int length;
+
+    /**
+     * The maximum number of bytes that can be stored in the current buffer
+     * before it must be reallocated.
+     */
+    int max_length;
+
     /**
      * The decoder to use when decoding the raw data received along this
      * stream, or NULL if no such decoder exists.
      */
     guacenc_decoder* decoder;
 
-    /**
-     * Arbitrary implementation-specific data associated with the stream.
-     */
-    void* data;
-
 } guacenc_image_stream;
 
 /**
- * Callback function which is invoked when a decoder has been assigned to an
+ * Mapping of image mimetype to corresponding decoder function.
- * image stream.
- *
- * @param stream
- *     The image stream that the decoder has been assigned to.
- *
- * @return
- *     Zero if initialization was successful, non-zero otherwise.
- */
-typedef int guacenc_decoder_init_handler(guacenc_image_stream* stream);
-
-/**
- * Callback function which is invoked when data has been received along an
- * image stream with an associated decoder.
- *
- * @param stream
- *     The image stream that the decoder was assigned to.
- *
- * @param data
- *     The chunk of data received along the image stream.
- *
- * @param length
- *     The length of the chunk of data received, in bytes.
- *
- * @return
- *     Zero if the provided data was processed successfully, non-zero
- *     otherwise.
- */
-typedef int guacenc_decoder_data_handler(guacenc_image_stream* stream,
-        unsigned char* data, int length);
-
-/**
- * Callback function which is invoked when an image stream with an associated
- * decoder has ended (reached end-of-stream). The image stream will contain
- * the required meta-information describing the drawing operation, including
- * the destination X/Y coordinates.
- *
- * @param stream
- *     The image stream that has ended.
- *
- * @param buffer
- *     The buffer to which the decoded image should be drawn.
- *
- * @return
- *     Zero if the end of the stream has been processed successfully and the
- *     resulting image has been rendered to the given buffer, non-zero
- *     otherwise.
- */
-typedef int guacenc_decoder_end_handler(guacenc_image_stream* stream,
-        guacenc_buffer* buffer);
-
-/**
- * Callback function which will be invoked when the data associated with an
- * image stream must be freed. This may happen at any time, and will not
- * necessarily occur only after the image stream has ended. It is possible
- * that an image stream will be in-progress at the end of a protocol dump, thus
- * the memory associated with the stream will need to be freed without ever
- * ending.
- *
- * @param stream
- *     The stream whose associated data must be freed.
- *
- * @return
- *     Zero if the data was successfully freed, non-zero otherwise.
- */
-typedef int guacenc_decoder_free_handler(guacenc_image_stream* stream);
-
-struct guacenc_decoder {
-
-    /**
-     * Callback invoked when this decoder has just been assigned to an image
-     * stream.
-     */
-    guacenc_decoder_init_handler* init_handler;
-
-    /**
-     * Callback invoked when data has been received along an image stream to
-     * which this decoder has been assigned.
-     */
-    guacenc_decoder_data_handler* data_handler;
-
-    /**
-     * Callback invoked when an image stream to which this decoder has been
-     * assigned has ended (reached end-of-stream).
-     */
-    guacenc_decoder_end_handler* end_handler;
-
-    /**
-     * Callback invoked when data associated with an image stream by this
-     * decoder must be freed.
-     */
-    guacenc_decoder_free_handler* free_handler;
-
-};
-
-/**
- * Mapping of image mimetype to corresponding decoder.
  */
 typedef struct guacenc_decoder_mapping {
 
@@ -180,8 +117,8 @@ typedef struct guacenc_decoder_mapping {
     const char* mimetype;
 
     /**
-     * The decoder to use when an image stream of the associated mimetype is
+     * The decoder function to use when an image stream of the associated
-     * received.
+     * mimetype is received.
      */
     guacenc_decoder* decoder;
 
@@ -238,9 +175,9 @@ guacenc_image_stream* guacenc_image_stream_alloc(int mask, int index,
         const char* mimetype, int x, int y);
 
 /**
- * Signals the decoder of the given image stream that a chunk of image data
+ * Appends newly-received data to the internal buffer of the given image
- * has been received. If no decoder is associated with the given image stream,
+ * stream, such that the entire received image can be fed to the decoder as one
- * this function has no effect.
+ * buffer once the stream ends.
  *
  * @param stream
  *     The image stream that received the data.
@@ -252,18 +189,19 @@ guacenc_image_stream* guacenc_image_stream_alloc(int mask, int index,
  *     The length of the chunk of data received, in bytes.
  *
  * @return
- *     Zero if the given data was handled successfully by the decoder, or
+ *     Zero if the given data was successfully appended to the in-progress
- *     non-zero if an error occurs.
+ *     image, non-zero if an error occurs.
  */
 int guacenc_image_stream_receive(guacenc_image_stream* stream,
         unsigned char* data, int length);
 
 /**
- * Signals the decoder of the given image stream that no more data will be
+ * Marks the end of the given image stream (no more data will be received) and
- * received and the image should be written to the given buffer as-is. If no
+ * invokes the associated decoder. The decoded image will be written to the
- * decoder is associated with the given image stream, this function has no
+ * given buffer as-is. If no decoder is associated with the given image stream,
- * effect. Meta-information describing the image draw operation itself is
+ * this function has no effect. Meta-information describing the image draw
- * stored within the guacenc_image_stream.
+ * operation itself is pulled from the guacenc_image_stream, having been stored
+ * there when the image stream was created.
  *
  * @param stream
  *     The image stream that has ended.

src/guacenc/jpeg.c

@@ -21,37 +21,14 @@
  */
 
 #include "config.h"
-#include "buffer.h"
-#include "image-stream.h"
 #include "jpeg.h"
 
+#include <cairo/cairo.h>
+
 #include <stdlib.h>
 
-int guacenc_jpeg_init(guacenc_image_stream* stream) {
+cairo_surface_t* guacenc_jpeg_decoder(unsigned char* data, int length) {
     /* STUB */
-    return 0;
+    return NULL;
 }
 
-int guacenc_jpeg_data(guacenc_image_stream* stream, unsigned char* data,
-        int length) {
-    /* STUB */
-    return 0;
-}
-
-int guacenc_jpeg_end(guacenc_image_stream* stream, guacenc_buffer* buffer) {
-    /* STUB */
-    return 0;
-}
-
-int guacenc_jpeg_free(guacenc_image_stream* stream) {
-    /* STUB */
-    return 0;
-}
-
-guacenc_decoder guacenc_jpeg_decoder = {
-    .init_handler = guacenc_jpeg_init,
-    .data_handler = guacenc_jpeg_data,
-    .end_handler  = guacenc_jpeg_end,
-    .free_handler = guacenc_jpeg_free
-};
-

src/guacenc/jpeg.h

@@ -29,7 +29,7 @@
 /**
  * Decoder implementation which handles "image/jpeg" images.
  */
-extern guacenc_decoder guacenc_jpeg_decoder;
+guacenc_decoder guacenc_jpeg_decoder;
 
 #endif
 

src/guacenc/png.c

@@ -21,37 +21,14 @@
  */
 
 #include "config.h"
-#include "buffer.h"
-#include "image-stream.h"
 #include "png.h"
 
+#include <cairo/cairo.h>
+
 #include <stdlib.h>
 
-int guacenc_png_init(guacenc_image_stream* stream) {
+cairo_surface_t* guacenc_png_decoder(unsigned char* data, int length) {
     /* STUB */
-    return 0;
+    return NULL;
 }
 
-int guacenc_png_data(guacenc_image_stream* stream, unsigned char* data,
-        int length) {
-    /* STUB */
-    return 0;
-}
-
-int guacenc_png_end(guacenc_image_stream* stream, guacenc_buffer* buffer) {
-    /* STUB */
-    return 0;
-}
-
-int guacenc_png_free(guacenc_image_stream* stream) {
-    /* STUB */
-    return 0;
-}
-
-guacenc_decoder guacenc_png_decoder = {
-    .init_handler = guacenc_png_init,
-    .data_handler = guacenc_png_data,
-    .end_handler  = guacenc_png_end,
-    .free_handler = guacenc_png_free
-};
-

src/guacenc/png.h

@@ -29,7 +29,7 @@
 /**
  * Decoder implementation which handles "image/png" images.
  */
-extern guacenc_decoder guacenc_png_decoder;
+guacenc_decoder guacenc_png_decoder;
 
 #endif
 

src/guacenc/webp.c

@@ -21,37 +21,14 @@
  */
 
 #include "config.h"
-#include "buffer.h"
-#include "image-stream.h"
 #include "webp.h"
 
+#include <cairo/cairo.h>
+
 #include <stdlib.h>
 
-int guacenc_webp_init(guacenc_image_stream* stream) {
+cairo_surface_t* guacenc_webp_decoder(unsigned char* data, int length) {
     /* STUB */
-    return 0;
+    return NULL;
 }
 
-int guacenc_webp_data(guacenc_image_stream* stream, unsigned char* data,
-        int length) {
-    /* STUB */
-    return 0;
-}
-
-int guacenc_webp_end(guacenc_image_stream* stream, guacenc_buffer* buffer) {
-    /* STUB */
-    return 0;
-}
-
-int guacenc_webp_free(guacenc_image_stream* stream) {
-    /* STUB */
-    return 0;
-}
-
-guacenc_decoder guacenc_webp_decoder = {
-    .init_handler = guacenc_webp_init,
-    .data_handler = guacenc_webp_data,
-    .end_handler  = guacenc_webp_end,
-    .free_handler = guacenc_webp_free
-};
-

src/guacenc/webp.h

@@ -29,7 +29,7 @@
 /**
  * Decoder implementation which handles "image/webp" images.
  */
-extern guacenc_decoder guacenc_webp_decoder;
+guacenc_decoder guacenc_webp_decoder;
 
 #endif