content/common/android/gin_java_bridge_value.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/common/android/gin_java_bridge_value.h"
   6
   7 namespace content {
   8
   9 namespace {
  10
  11 // The magic value is only used to prevent accidental attempts of reading
  12 // GinJavaBridgeValue from a random BinaryValue.  GinJavaBridgeValue is not
  13 // intended for scenarios where with BinaryValues are being used for anything
  14 // else than holding GinJavaBridgeValues.  If a need for such scenario ever
  15 // emerges, the best solution would be to extend GinJavaBridgeValue to be able
  16 // to wrap raw BinaryValues.
  17 const uint32 kHeaderMagic = 0xBEEFCAFE;
  18
  19 #pragma pack(push, 4)
  20 struct Header : public base::Pickle::Header {
  21   uint32 magic;
  22   int32 type;
  23 };
  24 #pragma pack(pop)
  25
  26 }
  27
  28 // static
  29 scoped_ptr<base::BinaryValue> GinJavaBridgeValue::CreateUndefinedValue() {
  30   GinJavaBridgeValue gin_value(TYPE_UNDEFINED);
  31   return make_scoped_ptr(gin_value.SerializeToBinaryValue());
  32 }
  33
  34 // static
  35 scoped_ptr<base::BinaryValue> GinJavaBridgeValue::CreateNonFiniteValue(
  36     float in_value) {
  37   GinJavaBridgeValue gin_value(TYPE_NONFINITE);
  38   gin_value.pickle_.WriteFloat(in_value);
  39   return make_scoped_ptr(gin_value.SerializeToBinaryValue());
  40 }
  41
  42 // static
  43 scoped_ptr<base::BinaryValue> GinJavaBridgeValue::CreateNonFiniteValue(
  44     double in_value) {
  45   return CreateNonFiniteValue(static_cast<float>(in_value)).Pass();
  46 }
  47
  48 // static
  49 scoped_ptr<base::BinaryValue> GinJavaBridgeValue::CreateObjectIDValue(
  50     int32 in_value) {
  51   GinJavaBridgeValue gin_value(TYPE_OBJECT_ID);
  52   gin_value.pickle_.WriteInt(in_value);
  53   return make_scoped_ptr(gin_value.SerializeToBinaryValue());
  54 }
  55
  56 // static
  57 bool GinJavaBridgeValue::ContainsGinJavaBridgeValue(const base::Value* value) {
  58   if (!value->IsType(base::Value::TYPE_BINARY))
  59     return false;
  60   const base::BinaryValue* binary_value =
  61       reinterpret_cast<const base::BinaryValue*>(value);
  62   if (binary_value->GetSize() < sizeof(Header))
  63     return false;
  64   base::Pickle pickle(binary_value->GetBuffer(), binary_value->GetSize());
  65   // Broken binary value: payload or header size is wrong
  66   if (!pickle.data() || pickle.size() - pickle.payload_size() != sizeof(Header))
  67     return false;
  68   Header* header = pickle.headerT<Header>();
  69   return (header->magic == kHeaderMagic &&
  70           header->type >= TYPE_FIRST_VALUE && header->type < TYPE_LAST_VALUE);
  71 }
  72
  73 // static
  74 scoped_ptr<const GinJavaBridgeValue> GinJavaBridgeValue::FromValue(
  75     const base::Value* value) {
  76   return scoped_ptr<const GinJavaBridgeValue>(
  77       value->IsType(base::Value::TYPE_BINARY)
  78           ? new GinJavaBridgeValue(
  79                 reinterpret_cast<const base::BinaryValue*>(value))
  80           : NULL);
  81 }
  82
  83 GinJavaBridgeValue::Type GinJavaBridgeValue::GetType() const {
  84   const Header* header = pickle_.headerT<Header>();
  85   DCHECK(header->type >= TYPE_FIRST_VALUE && header->type < TYPE_LAST_VALUE);
  86   return static_cast<Type>(header->type);
  87 }
  88
  89 bool GinJavaBridgeValue::IsType(Type type) const {
  90   return GetType() == type;
  91 }
  92
  93 bool GinJavaBridgeValue::GetAsNonFinite(float* out_value) const {
  94   if (GetType() == TYPE_NONFINITE) {
  95     base::PickleIterator iter(pickle_);
  96     return iter.ReadFloat(out_value);
  97   } else {
  98     return false;
  99   }
 100 }
 101
 102 bool GinJavaBridgeValue::GetAsObjectID(int32* out_object_id) const {
 103   if (GetType() == TYPE_OBJECT_ID) {
 104     base::PickleIterator iter(pickle_);
 105     return iter.ReadInt(out_object_id);
 106   } else {
 107     return false;
 108   }
 109 }
 110
 111 GinJavaBridgeValue::GinJavaBridgeValue(Type type) :
 112     pickle_(sizeof(Header)) {
 113   Header* header = pickle_.headerT<Header>();
 114   header->magic = kHeaderMagic;
 115   header->type = type;
 116 }
 117
 118 GinJavaBridgeValue::GinJavaBridgeValue(const base::BinaryValue* value)
 119     : pickle_(value->GetBuffer(), value->GetSize()) {
 120   DCHECK(ContainsGinJavaBridgeValue(value));
 121 }
 122
 123 base::BinaryValue* GinJavaBridgeValue::SerializeToBinaryValue() {
 124   return base::BinaryValue::CreateWithCopiedBuffer(
 125       reinterpret_cast<const char*>(pickle_.data()), pickle_.size());
 126 }
 127
 128 }  // namespace content