skia: Added SkDiscardableMemory interface.
Chrome's implementation of SkDiscardableMemory is provided here:
https://codereview.chromium.org/23206002. SkDiscardableMemory is
intended to be used for image caching.
R=reed@google.com, scroggo@google.com, hclam@chromium.org, jamesr@chromium.org
BUG=229120
Author=ernstm@chromium.org
Submitted on behalf of ernstm@chromium.org due to commit queue bug.
Review URL: https://codereview.chromium.org/22950012
git-svn-id: http://skia.googlecode.com/svn/trunk/src@10797 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/core/SkDiscardableMemory.h b/core/SkDiscardableMemory.h
new file mode 100644
index 0000000..ca17db3
--- /dev/null
+++ b/core/SkDiscardableMemory.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkDiscardableMemory_DEFINED
+#define SkDiscardableMemory_DEFINED
+
+#include "SkTypes.h"
+
+/**
+ * Interface for discardable memory. Implementation is provided by the
+ * embedder.
+ */
+class SkDiscardableMemory {
+
+public:
+ /**
+ * Factory method that creates, initializes and locks an SkDiscardableMemory
+ * object. If either of these steps fails, a NULL pointer will be returned.
+ */
+ static SkDiscardableMemory* Create(size_t bytes);
+
+ /** Must not be called while locked.
+ */
+ virtual ~SkDiscardableMemory() {}
+
+ /**
+ * Locks the memory, prevent it from being discarded. Once locked. you may
+ * obtain a pointer to that memory using the data() method.
+ *
+ * lock() may return false, indicating that the underlying memory was
+ * discarded and that the lock failed.
+ *
+ * Nested calls to lock are not allowed.
+ */
+ virtual bool lock() = 0;
+
+ /**
+ * Returns the current pointer for the discardable memory. This call is ONLY
+ * valid when the discardable memory object is locked.
+ */
+ virtual void* data() = 0;
+
+ /**
+ * Unlock the memory so that it can be purged by the system. Must be called
+ * after every successful lock call.
+ */
+ virtual void unlock() = 0;
+};
+
+#endif
diff --git a/ports/SkDiscardableMemory_none.cpp b/ports/SkDiscardableMemory_none.cpp
new file mode 100644
index 0000000..6559097
--- /dev/null
+++ b/ports/SkDiscardableMemory_none.cpp
@@ -0,0 +1,12 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkDiscardableMemory.h"
+
+SkDiscardableMemory* SkDiscardableMemory::Create(size_t bytes) {
+ return NULL;
+}
