DM: read image files without an extra copy

BUG=skia:
R=halcanary@google.com, reed@google.com, bsalomon@google.com, mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/185263012

git-svn-id: http://skia.googlecode.com/svn/trunk@13669 2bbb7eff-a529-9590-31e7-b0007b416f81

diff --git a/dm/DMWriteTask.cpp b/dm/DMWriteTask.cpp
index 04479e9..890a4bb 100644 (file)
--- a/dm/DMWriteTask.cpp
+++ b/dm/DMWriteTask.cpp
@@ -4,8 +4,9 @@
 #include "SkColorPriv.h"
 #include "SkCommandLineFlags.h"
 #include "SkImageEncoder.h"
-#include "SkString.h"
+#include "SkMallocPixelRef.h"
 #include "SkStream.h"
+#include "SkString.h"
 
 DEFINE_string2(writePath, w, "", "If set, write GMs here as .pngs.");
 
@@ -38,6 +39,8 @@ void WriteTask::makeDirOrFail(SkString dir) {
     }
 }
 
+namespace {
+
 // One file that first contains a .png of an SkBitmap, then its raw pixels.
 // We use this custom format to avoid premultiplied/unpremultiplied pixel conversions.
 struct PngAndRaw {
@@ -54,42 +57,45 @@ struct PngAndRaw {
             return false;
         }
 
+        // Pad out so the raw pixels start 4-byte aligned.
+        const uint32_t maxPadding = 0;
+        const size_t pos = stream.bytesWritten();
+        stream.write(&maxPadding, SkAlign4(pos) - pos);
+
         // Then write our secret raw pixels that only DM reads.
         SkAutoLockPixels lock(bitmap);
         return stream.write(bitmap.getPixels(), bitmap.getSize());
     }
 
     // This assumes bitmap already has allocated pixels of the correct size.
-    static bool Decode(const char* path, SkBitmap* bitmap) {
-        SkAutoTUnref<SkStreamRewindable> stream(SkStream::NewFromFile(path));
-        if (NULL == stream.get()) {
+    static bool Decode(const char* path, SkImageInfo info, SkBitmap* bitmap) {
+        SkAutoTUnref<SkData> data(SkData::NewFromFileName(path));
+        if (!data) {
             SkDebugf("Can't read %s.\n", path);
             return false;
         }
 
-        // The raw pixels are at the end of the stream.  Seek ahead to skip beyond the encoded PNG.
-        const size_t bitmapBytes = bitmap->getSize();
-        if (stream->getLength() < bitmapBytes) {
+        // The raw pixels are at the end of the file.  We'll skip the encoded PNG at the front.
+        const size_t rowBytes = info.minRowBytes();  // Assume densely packed.
+        const size_t bitmapBytes = info.getSafeSize(rowBytes);
+        if (data->size() < bitmapBytes) {
             SkDebugf("%s is too small to contain the bitmap we're looking for.\n", path);
             return false;
         }
-        SkAssertResult(stream->seek(stream->getLength() - bitmapBytes));
-
-        // Read the raw pixels.
-        // TODO(mtklein): can we install a pixelref that just hangs onto the stream instead of
-        // copying into a malloc'd buffer?
-        SkAutoLockPixels lock(*bitmap);
-        if (bitmapBytes != stream->read(bitmap->getPixels(), bitmapBytes)) {
-            SkDebugf("Couldn't read raw bitmap from %s at %lu of %lu.\n",
-                     path, stream->getPosition(), stream->getLength());
-            return false;
-        }
 
-        SkASSERT(stream->isAtEnd());
+        const size_t offset = data->size() - bitmapBytes;
+        SkAutoTUnref<SkPixelRef> pixels(
+            SkMallocPixelRef::NewWithData(info, rowBytes, NULL/*ctable*/, data, offset));
+        SkASSERT(pixels);
+
+        bitmap->setConfig(info, rowBytes);
+        bitmap->setPixelRef(pixels);
         return true;
     }
 };
 
+}  // namespace
+
 void WriteTask::draw() {
     SkString dir(FLAGS_writePath[0]);
     this->makeDirOrFail(dir);
@@ -144,8 +150,7 @@ bool WriteTask::Expectations::check(const Task& task, SkBitmap bitmap) const {
 
     const SkString path = path_to_expected_image(fRoot, task);
     SkBitmap expected;
-    expected.allocPixels(bitmap.info());
-    if (!PngAndRaw::Decode(path.c_str(), &expected)) {
+    if (!PngAndRaw::Decode(path.c_str(), bitmap.info(), &expected)) {
         return false;
     }
 

diff --git a/include/core/SkStream.h b/include/core/SkStream.h
index 50ed691..6e0ab56 100644 (file)
--- a/include/core/SkStream.h
+++ b/include/core/SkStream.h
@@ -363,6 +363,7 @@ public:
     */
     bool isValid() const { return fFILE != NULL; }
 
+    size_t bytesWritten() const;
     virtual bool write(const void* buffer, size_t size) SK_OVERRIDE;
     virtual void flush() SK_OVERRIDE;
 

diff --git a/src/core/SkStream.cpp b/src/core/SkStream.cpp
index 3350f82..8b4b82a 100644 (file)
--- a/src/core/SkStream.cpp
+++ b/src/core/SkStream.cpp
@@ -433,14 +433,20 @@ SkFILEWStream::SkFILEWStream(const char path[])
 
 SkFILEWStream::~SkFILEWStream()
 {
-    if (fFILE)
+    if (fFILE) {
         sk_fclose(fFILE);
+    }
+}
+
+size_t SkFILEWStream::bytesWritten() const {
+    return sk_ftell(fFILE);
 }
 
 bool SkFILEWStream::write(const void* buffer, size_t size)
 {
-    if (fFILE == NULL)
+    if (fFILE == NULL) {
         return false;
+    }
 
     if (sk_fwrite(buffer, size, fFILE) != size)
     {
@@ -454,8 +460,9 @@ bool SkFILEWStream::write(const void* buffer, size_t size)
 
 void SkFILEWStream::flush()
 {
-    if (fFILE)
+    if (fFILE) {
         sk_fflush(fFILE);
+    }
 }
 
 ////////////////////////////////////////////////////////////////////////