sketch SkValue API

src/core/SkValue.h

Index: src/core/SkValue.h
diff --git a/src/core/SkValue.h b/src/core/SkValue.h
new file mode 100644
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+++ b/src/core/SkValue.h
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+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkValue_DEFINED
+#define SkValue_DEFINED
+
+#include "SkTypes.h"
+#include <functional>
+
+class SkValue {
+public:
+    enum Type : uint32_t {
+        // 0-255 are reserved for built-in SkValue types.
+        Null,
+        Byte , S16 , U16 , S32 , U32 , S64 , U64 , F32 , F64 ,
+        Bytes, S16s, U16s, S32s, U32s, S64s, U64s, F32s, F64s,
+        Array,
+
+        // 256-2147483647 may be used by Skia for public Object types.
+
+
+        // 2147483648+ won't be used by Skia.  They're open for client-specific use, testing, etc.
+    };
+
+    enum Key : uint32_t {
+        // Each Object type may define its own namespace of Key values,
+        // so there are no pre-defined Keys here.
+        //
+        // This is just a reminder that they must fit in a uint32_t,
+        // and that their namespace is distinct from other uint32_ts (e.g. Type).
+    };
+
+    SkValue();
+    SkValue(const SkValue&);
+    SkValue(SkValue&&);
+
+    SkValue& operator=(const SkValue&);
+    SkValue& operator=(SkValue&&);
+
+    ~SkValue();
+
+    static SkValue FromS32(int32_t);
+    static SkValue FromU32(uint32_t);
+    static SkValue FromF32(float);
+    static SkValue FromBytes(const void*, size_t);  // Copies.
+    static SkValue Object(Type);
+
+    Type type() const;
+
+    // These remaining methods may assert they're called on a value of the appropriate type.
+
+    int32_t  s32() const;
+    uint32_t u32() const;
+    float    f32() const;
+
+    const void* bytes() const;
+    size_t      count() const;
+
+    void set(Key, SkValue);
+    const SkValue* get(Key) const;
+    void foreach(std::function<void(Key, const SkValue&)>) const;
+
+private:
+    class Bytes;
+    class Object;
+
+    Type fType;
+    union {
+        int32_t       fS32;
+        uint32_t      fU32;
+        float         fF32;
+        class Bytes*  fBytes;
+        class Object* fObject;
+    };
+};
+
+#endif//SkValue_DEFINED