Allow Mojo structs as map keys

mojo/public/cpp/bindings/lib/wtf_clone_equals_util.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_WTF_CLONE_EQUALS_UTIL_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_WTF_CLONE_EQUALS_UTIL_H_
 
 #include <type_traits>
 
 #include "mojo/public/cpp/bindings/lib/clone_equals_util.h"
+#include "mojo/public/cpp/bindings/struct_ptr.h"
+#include "third_party/WebKit/Source/wtf/HashFunctions.h"
 #include "third_party/WebKit/Source/wtf/HashMap.h"
 #include "third_party/WebKit/Source/wtf/Optional.h"
 #include "third_party/WebKit/Source/wtf/Vector.h"
+#include "third_party/WebKit/Source/wtf/text/StringHash.h"
 #include "third_party/WebKit/Source/wtf/text/WTFString.h"
 
 namespace mojo {
 namespace internal {
 
 template <typename T>
 struct CloneTraits<WTF::Vector<T>, false> {
   static WTF::Vector<T> Clone(const WTF::Vector<T>& input) {
     WTF::Vector<T> result;
     result.reserveCapacity(input.size());
@@ skipping 39 matching lines @@
 
     for (auto iter = a.begin(); iter != a_end; ++iter) {
       auto b_iter = b.find(iter->key);
       if (b_iter == b_end || !internal::Equals(iter->value, b_iter->value))
         return false;
     }
     return true;
   }
 };
 
+template <typename T>
+struct HashTraits<WTF::Vector<T>, false> {

[Sam McNally, 2016/09/21 04:57:58]

Ditto for these two.

[tibell, 2016/09/21 07:10:53]

Done.

+  static size_t Hash(size_t seed, const WTF::Vector<T>& value) {
+    for (size_t i = 0; i < value.size(); ++i) {
+      seed = Hash(seed, value[i]);
+    }
+    return seed;
+  }
+};
+
+template <typename K, typename V>
+struct HashTraits<WTF::HashMap<K, V>, false> {
+  static size_t Hash(size_t seed, const WTF::HashMap<K, V>& value) {
+    for (auto iter = value.begin(); iter != value.end(); ++iter) {
+      seed = Hash(seed, iter->key);
+      seed = Hash(seed, iter->value);
+    }
+    return seed;
+  }
+};
+
+template <>
+struct HashTraits<WTF::String, false> {
+  static size_t Hash(size_t seed, const WTF::String& value) {
+    return HashCombine(seed, WTF::StringHash::hash(value));
+  }
+};
+
+template <typename T>
+struct StructPtrHashFn {
+  static unsigned hash(const mojo::StructPtr<T>& value) {

[yzshen1, 2016/09/20 23:44:39]

nit: namespace is not needed (here and changes below)

[tibell, 2016/09/21 07:10:53]

Done.

These now all uses hashing/equality on the {Inlined}StructPtr itself, which
correctly takes nullability into account.

+    return mojo::internal::Hash(mojo::internal::kHashSeed, *value.get());

[yzshen1, 2016/09/20 23:44:39]

*value.get(): Is it possible to dereference null ptr here?

[tibell, 2016/09/21 07:10:53]

Done.

+  }
+  static bool equal(const mojo::StructPtr<T>& left,
+                    const mojo::StructPtr<T>& right) {
+    return left->Equals(*right);

[yzshen1, 2016/09/20 23:44:39]

ditto

[tibell, 2016/09/21 07:10:53]

Done.

+  }
+  static const bool safeToCompareToEmptyOrDeleted = false;
+};
+
+template <typename T>
+struct InlinedStructPtrHashFn {
+  static unsigned hash(const mojo::InlinedStructPtr<T>& value) {
+    return mojo::internal::Hash(mojo::internal::kHashSeed, *value.get());

[yzshen1, 2016/09/20 23:44:39]

ditto

[tibell, 2016/09/21 07:10:53]

Done.

+  }
+  static bool equal(const mojo::InlinedStructPtr<T>& left,
+                    const mojo::InlinedStructPtr<T>& right) {
+    return left->Equals(*right);

[yzshen1, 2016/09/20 23:44:39]

ditto

[tibell, 2016/09/21 07:10:53]

Done.

+  }
+  static const bool safeToCompareToEmptyOrDeleted = false;
+};
+
 }  // namespace internal
 }  // namespace mojo
 
+namespace WTF {
+
+template <typename T>
+struct DefaultHash<mojo::StructPtr<T>> {
+  using Hash = mojo::internal::StructPtrHashFn<T>;
+};
+
+template <typename T>
+struct HashTraits<mojo::StructPtr<T>>
+    : public GenericHashTraits<mojo::StructPtr<T>> {
+  static const bool hasIsEmptyValueFunction = true;
+  static bool isEmptyValue(const mojo::StructPtr<T>& value) {
+    return value.is_null();
+  }
+  static void constructDeletedValue(mojo::StructPtr<T>& slot, bool) {
+    mojo::StructPtr<T>::constructDeletedValue(slot);
+  }
+  static bool isDeletedValue(const mojo::StructPtr<T>& value) {
+    return value.isHashTableDeletedValue();
+  }
+};
+
+template <typename T>
+struct DefaultHash<mojo::InlinedStructPtr<T>> {
+  using Hash = mojo::internal::InlinedStructPtrHashFn<T>;
+};
+
+template <typename T>
+struct HashTraits<mojo::InlinedStructPtr<T>>
+    : public GenericHashTraits<mojo::InlinedStructPtr<T>> {
+  static const bool hasIsEmptyValueFunction = true;
+  static bool isEmptyValue(const mojo::InlinedStructPtr<T>& value) {
+    return value.is_null();
+  }
+  static void constructDeletedValue(mojo::InlinedStructPtr<T>& slot, bool) {
+    mojo::InlinedStructPtr<T>::constructDeletedValue(slot);
+  }
+  static bool isDeletedValue(const mojo::InlinedStructPtr<T>& value) {
+    return value.isHashTableDeletedValue();
+  }
+};
+
+}  // namespace WTF
+
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_WTF_CLONE_EQUALS_UTIL_H_