Merge AssetStream with AssetStreamAdaptor.

Add enums to the constructor for AssetStreamAdaptor to choose the
different behaviors used by the (former) two different classes.

The old clients of AssetStream now get the following features of
AssetStreamAdaptor
- Debugging statements on error.
- The stream is an SkStreamRewindable.
- getLength() returns the correct value, and the old way of getting
  the length (read(NULL, 0)) is no longer implemented, since it is
  no longer used.
- isAtEnd() returns the correct value. ToT Skia makes it pure virtual,
  so some implementation is necessary.

Change-Id: I2a5395914e4f53830aaefee396556459083a1c56

5 files changed, 50 insertions, 65 deletions

diff --git a/core/jni/android/graphics/BitmapFactory.cpp b/core/jni/android/graphics/BitmapFactory.cpp
index 80bd3e2..944b732 100644
--- a/core/jni/android/graphics/BitmapFactory.cpp
+++ b/core/jni/android/graphics/BitmapFactory.cpp
@@ -541,7 +541,9 @@ static jobject nativeDecodeAsset(JNIEnv* env, jobject clazz, jint native_asset,
     } else {
         // since we know we'll be done with the asset when we return, we can
         // just use a simple wrapper
-        stream = new AssetStreamAdaptor(asset);
+        stream = new AssetStreamAdaptor(asset,
+                                        AssetStreamAdaptor::kNo_OwnAsset,
+                                        AssetStreamAdaptor::kNo_HasMemoryBase);
     }
     SkAutoUnref aur(stream);
     return doDecode(env, stream, padding, options, forcePurgeable, forcePurgeable);
diff --git a/core/jni/android/graphics/Movie.cpp b/core/jni/android/graphics/Movie.cpp
index feb2dec..55be7c1 100644
--- a/core/jni/android/graphics/Movie.cpp
+++ b/core/jni/android/graphics/Movie.cpp
@@ -85,7 +85,9 @@ static void movie_draw(JNIEnv* env, jobject movie, jobject canvas,
 static jobject movie_decodeAsset(JNIEnv* env, jobject clazz, jint native_asset) {
     android::Asset* asset = reinterpret_cast<android::Asset*>(native_asset);
     if (asset == NULL) return NULL;
-    SkAutoTUnref<SkStreamRewindable> stream (new android::AssetStreamAdaptor(asset));
+    SkAutoTUnref<SkStreamRewindable> stream (new android::AssetStreamAdaptor(asset,
+            android::AssetStreamAdaptor::kNo_OwnAsset,
+            android::AssetStreamAdaptor::kNo_HasMemoryBase));
     SkMovie* moov = SkMovie::DecodeStream(stream.get());
     return create_jmovie(env, moov);
 }
diff --git a/core/jni/android/graphics/TypefaceImpl.cpp b/core/jni/android/graphics/TypefaceImpl.cpp
index 8874db8..f6d3a6e 100644
--- a/core/jni/android/graphics/TypefaceImpl.cpp
+++ b/core/jni/android/graphics/TypefaceImpl.cpp
@@ -32,68 +32,10 @@
 #endif
 
 #include "TypefaceImpl.h"
+#include "Utils.h"
 
 namespace android {
 
-class AssetStream : public SkStream {
-public:
-    AssetStream(Asset* asset, bool hasMemoryBase) : fAsset(asset)
-    {
-        fMemoryBase = hasMemoryBase ? fAsset->getBuffer(false) : NULL;
-    }
-
-    virtual ~AssetStream()
-    {
-        delete fAsset;
-    }
-
-    virtual const void* getMemoryBase()
-    {
-        return fMemoryBase;
-    }
-
-    virtual bool rewind()
-    {
-        off64_t pos = fAsset->seek(0, SEEK_SET);
-        return pos != (off64_t)-1;
-    }
-
-    virtual size_t read(void* buffer, size_t size)
-    {
-        ssize_t amount;
-
-        if (NULL == buffer)
-        {
-            if (0 == size)  // caller is asking us for our total length
-                return fAsset->getLength();
-
-            // asset->seek returns new total offset
-            // we want to return amount that was skipped
-
-            off64_t oldOffset = fAsset->seek(0, SEEK_CUR);
-            if (-1 == oldOffset)
-                return 0;
-            off64_t newOffset = fAsset->seek(size, SEEK_CUR);
-            if (-1 == newOffset)
-                return 0;
-
-            amount = newOffset - oldOffset;
-        }
-        else
-        {
-            amount = fAsset->read(buffer, size);
-        }
-
-        if (amount < 0)
-            amount = 0;
-        return amount;
-    }
-
-private:
-    Asset*      fAsset;
-    const void* fMemoryBase;
-};
-
 #ifdef USE_MINIKIN
 
 // Any weight greater than or equal to this is considered "bold" for
@@ -194,7 +136,9 @@ TypefaceImpl* TypefaceImpl_createFromFile(const char* filename) {
 }
 
 TypefaceImpl* TypefaceImpl_createFromAsset(Asset* asset) {
-    SkStream* stream = new AssetStream(asset, true);
+    SkStream* stream = new AssetStreamAdaptor(asset,
+                                              AssetStreamAdaptor::kYes_OwnAsset,
+                                              AssetStreamAdaptor::kYes_HasMemoryBase);
     SkTypeface* face = SkTypeface::CreateFromStream(stream);
     // SkTypeFace::CreateFromStream calls ref() on the stream, so we
     // need to unref it here or it won't be freed later on
@@ -234,7 +178,9 @@ TypefaceImpl* TypefaceImpl_createFromFile(const char* filename) {
 }
 
 TypefaceImpl* TypefaceImpl_createFromAsset(Asset* asset) {
-    SkStream* stream = new AssetStream(asset, true);
+    SkStream* stream = new AssetStreamAdaptor(asset,
+                                              AssetStreamAdaptor::kYes_OwnAsset,
+                                              AssetStreamAdaptor::kYes_HasMemoryBase);
     SkTypeface* face = SkTypeface::CreateFromStream(stream);
     // SkTypeFace::CreateFromStream calls ref() on the stream, so we
     // need to unref it here or it won't be freed later on
diff --git a/core/jni/android/graphics/Utils.cpp b/core/jni/android/graphics/Utils.cpp
index b7d1f3a..eb416cb 100644
--- a/core/jni/android/graphics/Utils.cpp
+++ b/core/jni/android/graphics/Utils.cpp
@@ -19,6 +19,21 @@
 
 using namespace android;
 
+AssetStreamAdaptor::AssetStreamAdaptor(Asset* asset, OwnAsset ownAsset,
+                                       HasMemoryBase hasMemoryBase)
+    : fAsset(asset)
+    , fMemoryBase(kYes_HasMemoryBase == hasMemoryBase ?
+                  asset->getBuffer(false) : NULL)
+    , fOwnAsset(ownAsset)
+{
+}
+
+AssetStreamAdaptor::~AssetStreamAdaptor() {
+    if (kYes_OwnAsset == fOwnAsset) {
+        delete fAsset;
+    }
+}
+
 bool AssetStreamAdaptor::rewind() {
     off64_t pos = fAsset->seek(0, SEEK_SET);
     if (pos == (off64_t)-1) {
diff --git a/core/jni/android/graphics/Utils.h b/core/jni/android/graphics/Utils.h
index a1ac72a..b90593c 100644
--- a/core/jni/android/graphics/Utils.h
+++ b/core/jni/android/graphics/Utils.h
@@ -28,16 +28,36 @@ namespace android {
 
 class AssetStreamAdaptor : public SkStreamRewindable {
 public:
-    AssetStreamAdaptor(Asset* a) : fAsset(a) {}
+    // Enum passed to constructor. If set to kYes_OwnAsset,
+    // the passed in Asset will be deleted upon destruction.
+    enum OwnAsset {
+        kYes_OwnAsset,
+        kNo_OwnAsset,
+    };
+
+    // Enum passed to constructor. If set to kYes_HasMemoryBase,
+    // getMemoryBase will return the Asset's buffer.
+    enum HasMemoryBase {
+        kYes_HasMemoryBase,
+        kNo_HasMemoryBase,
+    };
+
+    AssetStreamAdaptor(Asset*, OwnAsset, HasMemoryBase);
+    ~AssetStreamAdaptor();
+
     virtual bool rewind();
     virtual size_t read(void* buffer, size_t size);
     virtual bool hasLength() const { return true; }
     virtual size_t getLength() const;
     virtual bool isAtEnd() const;
 
+    virtual const void* getMemoryBase() { return fMemoryBase; }
+
     virtual SkStreamRewindable* duplicate() const;
 private:
-    Asset*  fAsset;
+    Asset*              fAsset;
+    const void* const   fMemoryBase;
+    const OwnAsset      fOwnAsset;
 };
 
 /**