Initial version of Blimp BlobCache.

blimp/common/compositor/webp_decoder.cc

Index: blimp/common/compositor/webp_decoder.cc
diff --git a/blimp/common/compositor/webp_decoder.cc b/blimp/common/compositor/webp_decoder.cc
index 7f4d3637d618eaed36ec202bc78e0aa0a6d9db8a..9293da20682d47a5609028f5a4d108222b485c2a 100644
--- a/blimp/common/compositor/webp_decoder.cc
+++ b/blimp/common/compositor/webp_decoder.cc
@@ -4,12 +4,33 @@
 
 #include "blimp/common/compositor/webp_decoder.h"
 
+#include "base/lazy_instance.h"
 #include "base/logging.h"
+#include "base/numerics/safe_conversions.h"
+#include "base/sha1.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
+#include "blimp/common/blob_cache/blob_cache.h"
+#include "blimp/common/blob_cache/infinite_blob_cache.h"
+#include "blimp/common/proto/blob_cache.pb.h"
 #include "third_party/libwebp/webp/decode.h"
 #include "third_party/libwebp/webp/demux.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 
 namespace blimp {
+namespace {
+std::string ToSHA1HexString(const void* data, size_t data_size) {

[Kevin M, 2016/04/13 23:29:52]

What about using binary SHA1 for transmission and just converting to
human-readable hex for display?

[nyquist, 2016/04/14 19:33:23]

Done. For now I also keep the cache in hex-format, but transmission is in bytes
like you said here. Is that OK?

+  unsigned char sha1_hash[base::kSHA1Length];
+  base::SHA1HashBytes(static_cast<const unsigned char*>(data), data_size,
+                      sha1_hash);
+  return base::ToLowerASCII(base::HexEncode(sha1_hash, base::kSHA1Length));
+}
+
+// TODO(nyquist): Make this not be infinite size.
+static base::LazyInstance<InfiniteBlobCache> g_blob_cache =
+    LAZY_INSTANCE_INITIALIZER;
+
+}  // namespace
 
 bool WebPDecoder(const void* input, size_t input_size, SkBitmap* bitmap) {
   DCHECK(bitmap);
@@ -24,6 +45,33 @@ bool WebPDecoder(const void* input, size_t input_size, SkBitmap* bitmap) {
   // Treat the input as uint8_t.
   WebPData data = {reinterpret_cast<const uint8_t*>(input), input_size};

[Kevin M, 2016/04/13 23:29:52]

Brace initialization is blacklisted. Sowwy. :(

[Kevin M, 2016/04/13 23:29:53]

Pick a better name?

[vmpstr, 2016/04/13 23:48:02]

Soon though, right? I think pkasting might be trying to allow it.

[nyquist, 2016/04/14 19:33:23]

Done.

 
+  if (input_size < 40) {
+    LOG(WARNING) << "Throwing away tiny input with size " << input_size;

[Kevin M, 2016/04/13 23:29:52]

How about DLOG? Is this actionable for release builds?

Can you add a comment about why we might be seeing tiny inputs in the first
place?

[nyquist, 2016/04/14 19:33:23]

Done.

+    return false;
+  }
+
+  bool found_in_cache = false;

[Kevin M, 2016/04/13 23:29:52]

Move this declaration down, just above the ParseFromArray block.

[nyquist, 2016/04/14 19:33:23]

Done.

+  // Declared here to still be in scope while decoding WebP data.
+  scoped_refptr<RefCountedVector> cached(new RefCountedVector);
+
+  std::unique_ptr<BlobCacheImageIdentifier> deserialized(
+      new BlobCacheImageIdentifier);
+  int signed_size = base::checked_cast<int>(input_size);
+  if (deserialized->ParseFromArray(input, signed_size)) {
+    if (g_blob_cache.Get().Contains(deserialized->id())) {
+      cached = g_blob_cache.Get().Get(deserialized->id());
+      // Overwrite previously initialized WebPData.
+      data.bytes = cached.get()->data.data();
+      data.size = cached.get()->data.size();
+      VLOG(2) << "Found SHA1 " << deserialized->id()
+              << " with size = " << data.size;
+      found_in_cache = true;
+    } else {
+      LOG(WARNING) << "Did not find cached image with SHA1: "
+                   << deserialized->id();
+    }
+  }
+
   // Read WebP feature information into |config.input|, which is a
   // WebPBitstreamFeatures. It contains information such as width, height and
   // whether the WebP image has an alpha channel or not.
@@ -69,6 +117,17 @@ bool WebPDecoder(const void* input, size_t input_size, SkBitmap* bitmap) {
     LOG(WARNING) << "Failed to decode WebP data.";
     return false;
   }
+
+  if (!found_in_cache) {
+    std::string sha1 = ToSHA1HexString(data.bytes, data.size);
+    VLOG(2) << "Inserting image to cache with SHA1: " << sha1
+            << " size: " << data.size;
+    scoped_refptr<RefCountedVector> to_cache(new RefCountedVector);
+    for (size_t i = 0; i < data.size; ++i)

[Kevin M, 2016/04/13 23:29:52]

Use braces for single lines (consistent with rest of blimp)

[nyquist, 2016/04/14 19:33:23]

Done.

+      to_cache.get()->data.push_back(data.bytes[i]);
+    g_blob_cache.Get().Put(sha1, to_cache);

[Kevin M, 2016/04/13 23:29:53]

std::move(to_cache)

[nyquist, 2016/04/14 19:33:23]

Done.

+  }
+
   return true;
 }