Reland "Handle different types of streams in different jpeg source managers"

For streams that are memory backed (stream->getMemoryBase() returns
a non-null ptr and hasLength() returns true), handle the stream
with skjpeg_mem_source_mgr, which directly assigns memory base to
the source manager.  For other non memory backed streams, handle the
stream with skjpeg_buffered_source_mgr, which is renamed from
the old skjpeg_source_mgr with no implementation change.

Original Author: cjbao <cathy.bao@intel.com>
https://skia-review.googlesource.com/c/17296/

Bug: skia:
Change-Id: I0885c5114083f976a9c08afe5954434196762e39
Reviewed-on: https://skia-review.googlesource.com/18933
Reviewed-by: Mike Klein <mtklein@chromium.org>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Matt Sarett <msarett@google.com>

1 files changed, 61 insertions, 20 deletions

diff --git a/src/codec/SkJpegUtility.cpp b/src/codec/SkJpegUtility.cpp
index 2cf36bacf1..c9c8d3b11c 100644
--- a/src/codec/SkJpegUtility.cpp
+++ b/src/codec/SkJpegUtility.cpp
@@ -10,9 +10,22 @@
 #include "SkCodecPriv.h"
 
 /*
- * Initialize the source manager
+ * Call longjmp to continue execution on an error
  */
-static void sk_init_source(j_decompress_ptr dinfo) {
+void skjpeg_err_exit(j_common_ptr dinfo) {
+    // Simply return to Skia client code
+    // JpegDecoderMgr will take care of freeing memory
+    skjpeg_error_mgr* error = (skjpeg_error_mgr*) dinfo->err;
+    (*error->output_message) (dinfo);
+    longjmp(error->fJmpBuf, 1);
+}
+
+// Functions for buffered sources //
+
+/*
+ * Initialize the buffered source manager
+ */
+static void sk_init_buffered_source(j_decompress_ptr dinfo) {
     skjpeg_source_mgr* src = (skjpeg_source_mgr*) dinfo->src;
     src->next_input_byte = (const JOCTET*) src->fBuffer;
     src->bytes_in_buffer = 0;
@@ -21,7 +34,7 @@ static void sk_init_source(j_decompress_ptr dinfo) {
 /*
  * Fill the input buffer from the stream
  */
-static boolean sk_fill_input_buffer(j_decompress_ptr dinfo) {
+static boolean sk_fill_buffered_input_buffer(j_decompress_ptr dinfo) {
     skjpeg_source_mgr* src = (skjpeg_source_mgr*) dinfo->src;
     size_t bytes = src->fStream->read(src->fBuffer, skjpeg_source_mgr::kBufferSize);
 
@@ -38,7 +51,7 @@ static boolean sk_fill_input_buffer(j_decompress_ptr dinfo) {
 /*
  * Skip a certain number of bytes in the stream
  */
-static void sk_skip_input_data(j_decompress_ptr dinfo, long numBytes) {
+static void sk_skip_buffered_input_data(j_decompress_ptr dinfo, long numBytes) {
     skjpeg_source_mgr* src = (skjpeg_source_mgr*) dinfo->src;
     size_t bytes = (size_t) numBytes;
 
@@ -69,6 +82,35 @@ static void sk_term_source(j_decompress_ptr dinfo)
     // need to modify SkJpegCodec to call jpeg_finish_decompress().
 }
 
+// Functions for memory backed sources //
+
+/*
+ * Initialize the mem backed source manager
+ */
+static void sk_init_mem_source(j_decompress_ptr dinfo) {
+    /* no work necessary here, all things are done in constructor */
+}
+
+static void sk_skip_mem_input_data (j_decompress_ptr cinfo, long num_bytes) {
+    jpeg_source_mgr* src = cinfo->src;
+    size_t bytes = static_cast<size_t>(num_bytes);
+    if(bytes > src->bytes_in_buffer) {
+        src->next_input_byte = nullptr;
+        src->bytes_in_buffer = 0;
+    } else {
+        src->next_input_byte += bytes;
+        src->bytes_in_buffer -= bytes;
+    }
+}
+
+static boolean sk_fill_mem_input_buffer (j_decompress_ptr cinfo) {
+    /* The whole JPEG data is expected to reside in the supplied memory,
+     * buffer, so any request for more data beyond the given buffer size
+     * is treated as an error.
+     */
+    return false;
+}
+
 /*
  * Constructor for the source manager that we provide to libjpeg
  * We provide skia implementations of all of the stream processing functions required by libjpeg
@@ -76,20 +118,19 @@ static void sk_term_source(j_decompress_ptr dinfo)
 skjpeg_source_mgr::skjpeg_source_mgr(SkStream* stream)
     : fStream(stream)
 {
-    init_source = sk_init_source;
-    fill_input_buffer = sk_fill_input_buffer;
-    skip_input_data = sk_skip_input_data;
-    resync_to_restart = jpeg_resync_to_restart;
-    term_source = sk_term_source;
-}
-
-/*
- * Call longjmp to continue execution on an error
- */
-void skjpeg_err_exit(j_common_ptr dinfo) {
-    // Simply return to Skia client code
-    // JpegDecoderMgr will take care of freeing memory
-    skjpeg_error_mgr* error = (skjpeg_error_mgr*) dinfo->err;
-    (*error->output_message) (dinfo);
-    longjmp(error->fJmpBuf, 1);
+    if (stream->hasLength() && stream->getMemoryBase()) {
+        init_source = sk_init_mem_source;
+        fill_input_buffer = sk_fill_mem_input_buffer;
+        skip_input_data = sk_skip_mem_input_data;
+        resync_to_restart = jpeg_resync_to_restart;
+        term_source = sk_term_source;
+        bytes_in_buffer = static_cast<size_t>(stream->getLength());
+        next_input_byte = static_cast<const JOCTET*>(stream->getMemoryBase());
+    } else {
+        init_source = sk_init_buffered_source;
+        fill_input_buffer = sk_fill_buffered_input_buffer;
+        skip_input_data = sk_skip_buffered_input_data;
+        resync_to_restart = jpeg_resync_to_restart;
+        term_source = sk_term_source;
+    }
 }