SkValue: implementation, unit test

src/core/SkValue.cpp

Index: src/core/SkValue.cpp
diff --git a/src/core/SkValue.cpp b/src/core/SkValue.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..3ec33f6781f994f2858a4df17a7a5a7ff827d9a5
--- /dev/null
+++ b/src/core/SkValue.cpp
@@ -0,0 +1,221 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include <unordered_map>
+#include <vector>
+
+#include "SkData.h"
+#include "SkMatrix.h"
+#include "SkValue.h"
+
+class SkValue::Obj {
+public:
+    void set(SkValue::Key k, SkValue&& v) { fMap[k] = std::move(v);  }
+    const SkValue* get(SkValue::Key k) const {
+        auto it = fMap.find(k);
+        return it != fMap.end() ? &it->second : nullptr;
+    }
+    void foreach(std::function<void(Key, const SkValue&)> fn) const {
+        for (const auto& pair : fMap) {
+            fn(pair.first, pair.second);
+        }
+    }
+
+private:
+    std::unordered_map<SkValue::Key, SkValue> fMap;
+};
+
+class SkValue::Arr {
+public:
+    size_t length() const { return fVec.size(); }
+    void append(SkValue&& val) { fVec.emplace_back(std::move(val)); }
+    const SkValue& at(size_t index) const {
+        SkASSERT(index < fVec.size());
+        return fVec[index];
+    }
+
+private:
+    std::vector<SkValue> fVec;
+};
+
+SkValue::SkValue() : fType(Null) {}
+
+SkValue::SkValue(const SkValue& o) {
+    memcpy(this, &o, sizeof(o));
+    if (this->isData()) {
+        fBytes->ref();
+    } else if (this->isObject()) {
+        fObject = new Obj(*fObject);
+    } else if (Array == fType) {
+        fArray = new Arr(*fArray);
+    }
+}
+
+SkValue::SkValue(SkValue&& o) {
+    memcpy(this, &o, sizeof(o));
+    new (&o) SkValue();
+}
+
+SkValue& SkValue::operator=(const SkValue& o) {
+    if (this != &o) {
+        this->~SkValue();
+        new (this) SkValue(o);
+    }
+    return *this;
+}
+
+SkValue& SkValue::operator=(SkValue&& o) {
+    if (this != &o) {
+        this->~SkValue();
+        new (this) SkValue(std::move(o));
+    }
+    return *this;
+}
+
+SkValue::~SkValue() {
+    if (this->isData()) {
+        fBytes->unref();
+    } else if (this->isObject()) {
+        delete fObject;
+    } else if (Array == fType) {
+        delete fArray;
+    }
+}
+
+template <typename T>
+SkValue SkValue::FromT(SkValue::Type type, T SkValue::*mp, T t) {
+    SkValue v;
+    v.fType = type;
+    v.*mp = t;
+    return v;
+}
+
+SkValue SkValue::FromS32(int32_t  x) { return FromT(S32, &SkValue::fS32, x); }
+SkValue SkValue::FromU32(uint32_t x) { return FromT(U32, &SkValue::fU32, x); }
+SkValue SkValue::FromF32(float    x) { return FromT(F32, &SkValue::fF32, x); }
+
+int32_t  SkValue::s32() const { SkASSERT(S32 == fType); return fS32; }
+uint32_t SkValue::u32() const { SkASSERT(U32 == fType); return fU32; }
+float    SkValue::f32() const { SkASSERT(F32 == fType); return fF32; }
+
+SkValue SkValue::FromBytes(SkData* data) {
+    if (!data) {
+        return SkValue();
+    }
+    SkValue v;
+    v.fType = Bytes;
+    v.fBytes = SkRef(data);
+    return v;
+}
+
+SkValue SkValue::Object(SkValue::Type t) {
+    SkValue v;
+    v.fType = t;
+    SkASSERT(v.isObject());
+    v.fObject = new Obj;
+    return v;
+}
+
+SkValue SkValue::ValueArray() {
+    SkValue v;
+    v.fType = Array;
+    v.fArray = new Arr;
+    return v;
+}
+
+SkData* SkValue::bytes() const {
+    SkASSERT(this->isData());
+    return fBytes;
+}
+
+void SkValue::set(SkValue::Key k, SkValue v) {
+    SkASSERT(this->isObject());
+    fObject->set(k, std::move(v));
+}
+
+void SkValue::foreach(std::function<void(Key, const SkValue&)> fn) const {
+    SkASSERT(this->isObject());
+    fObject->foreach(fn);
+}
+
+size_t SkValue::length() const {
+    SkASSERT(Array == fType);
+    return fArray->length();
+}
+
+const SkValue& SkValue::at(size_t index) const {
+    SkASSERT(Array == fType);
+    return fArray->at(index);
+}
+
+void SkValue::append(SkValue val) {
+    SkASSERT(Array == fType);
+    fArray->append(std::move(val));
+}
+
+template <typename T>
+const T* SkValue::AsArray(SkValue::Type t, int* count) const {

[mtklein, 2016/01/20 15:47:50]

I'm getting confused by AsArray, Array, ValueArray.

This is not static, so its name should start lower case.

asTs to match FromTs?

[hal.canary, 2016/01/20 16:38:56]

Righto.  Done.

What should ValueArray be named?  I don't know.  CreateArray?

+    SkASSERT(t == fType);

[mtklein, 2016/01/20 15:47:50]

merge related SkASSERT(t == fType && this->isData()) ?

[hal.canary, 2016/01/20 16:38:56]

Done.

+    SkASSERT(count);
+    SkASSERT(this->isData());
+    *count = fBytes->size() / sizeof(T);
+    return static_cast<const T*>(fBytes->data());
+}
+
+const uint16_t* SkValue::u16s(int* c) const { return AsArray<uint16_t>(U16s, c); }
+const uint32_t* SkValue::u32s(int* c) const { return AsArray<uint32_t>(U32s, c); }
+const float*    SkValue::f32s(int* c) const { return AsArray<float   >(F32s, c); }
+
+template <typename T>
+SkValue SkValue::FromTs(SkValue::Type type, SkData* data) {
+    SkValue val;
+    val.fType = type;
+    val.fBytes = SkRef(data);
+    SkASSERT(val.isData());
+    SkASSERT(0 == (reinterpret_cast<uintptr_t>(data->bytes()) & (sizeof(T)-1)));
+    return val;
+}
+
+SkValue SkValue::FromU16s(SkData* d) { return FromTs<uint16_t>(U16s, d); }
+SkValue SkValue::FromU32s(SkData* d) { return FromTs<uint32_t>(U32s, d); }
+SkValue SkValue::FromF32s(SkData* d) { return FromTs<   float>(F32s, d); }
+
+////////////////////////////////////////////////////////////////////////////////
+
+template<> SkValue SkToValue<SkMatrix>(const SkMatrix& mat) {
+    auto val = SkValue::Object(SkValue::Matrix);
+    for (int i = 0; i < 9; ++i) {
+        if (mat[i] != SkMatrix::I()[i]) {
+            val.set(i, SkValue::FromF32(mat[i]));
+        }
+    }
+    return val;
+}
+
+template<> bool SkFromValue<SkMatrix>(const SkValue& val, SkMatrix* m){
+    SkASSERT(val.type() == SkValue::Matrix);
+    if (val.type() != SkValue::Matrix) {
+        return false;
+    }
+    *m = SkMatrix::I();
+    bool good = true;
+    auto fn = [&](SkValue::Key key, const SkValue& v) {
+        if (key < 9) {
+            if (v.type() != SkValue::F32) {
+                SkASSERT(false);
+                good = false;
+            } else {
+                (*m)[key] = v.f32();
+            }
+        } else {
+            SkASSERT(false);
+            good = false;
+        }
+    };
+    val.foreach(fn);
+    return good;
+}