pdf/post_message_receiver.h

   1 // Copyright 2021 The Chromium Authors
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef PDF_POST_MESSAGE_RECEIVER_H_
   6 #define PDF_POST_MESSAGE_RECEIVER_H_
   7
   8 #include <memory>
   9
  10 #include "base/memory/raw_ptr.h"
  11 #include "base/memory/scoped_refptr.h"
  12 #include "base/memory/weak_ptr.h"
  13 #include "base/values.h"
  14 #include "gin/interceptor.h"
  15 #include "gin/public/wrapper_info.h"
  16 #include "gin/wrappable.h"
  17 #include "v8/include/v8.h"
  18
  19 namespace base {
  20 class SequencedTaskRunner;
  21 }  // namespace base
  22
  23 namespace gin {
  24 class ObjectTemplateBuilder;
  25 }  // namespace gin
  26
  27 namespace chrome_pdf {
  28
  29 class V8ValueConverter;
  30
  31 // Implements the `postMessage()` API exposed to the plugin embedder. The
  32 // received messages are converted and forwarded to the `Client`.
  33 // `PostMessageReceiver`'s lifetime is managed by the V8 garbage collector,
  34 // meaning it can outlive the `Client`. Messages are dropped if the `Client` is
  35 // destroyed.
  36 class PostMessageReceiver final : public gin::Wrappable<PostMessageReceiver>,
  37                                   public gin::NamedPropertyInterceptor {
  38  public:
  39   // The interface for a plugin client that handles messages from its embedder.
  40   class Client {
  41    public:
  42     // Handles converted messages from the embedder.
  43     virtual void OnMessage(const base::Value::Dict& message) = 0;
  44
  45    protected:
  46     Client() = default;
  47     ~Client() = default;
  48   };
  49
  50   static gin::WrapperInfo kWrapperInfo;
  51
  52   // Creates a scriptable object with an implemented `postMessage()` method.
  53   // Messages are posted asynchronously to `client` using `client_task_runner`.
  54   static v8::Local<v8::Object> Create(
  55       v8::Isolate* isolate,
  56       base::WeakPtr<V8ValueConverter> v8_value_converter,
  57       base::WeakPtr<Client> client,
  58       scoped_refptr<base::SequencedTaskRunner> client_task_runner);
  59
  60   PostMessageReceiver(const PostMessageReceiver&) = delete;
  61   PostMessageReceiver& operator=(const PostMessageReceiver&) = delete;
  62
  63  protected:
  64   ~PostMessageReceiver() override;
  65
  66  private:
  67   PostMessageReceiver(
  68       v8::Isolate* isolate,
  69       base::WeakPtr<V8ValueConverter> v8_value_converter,
  70       base::WeakPtr<Client> client,
  71       scoped_refptr<base::SequencedTaskRunner> client_task_runner);
  72
  73   // gin::Wrappable:
  74   gin::ObjectTemplateBuilder GetObjectTemplateBuilder(
  75       v8::Isolate* isolate) override;
  76   const char* GetTypeName() override;
  77
  78   // gin::NamedPropertyInterceptor:
  79   v8::Local<v8::Value> GetNamedProperty(v8::Isolate* isolate,
  80                                         const std::string& property) override;
  81   std::vector<std::string> EnumerateNamedProperties(
  82       v8::Isolate* isolate) override;
  83
  84   // Lazily creates and retrieves `function_template_`.
  85   v8::Local<v8::FunctionTemplate> GetFunctionTemplate();
  86
  87   // Implements the `postMessage()` method called by the embedder.
  88   void PostMessage(v8::Local<v8::Value> message);
  89
  90   base::WeakPtr<V8ValueConverter> v8_value_converter_;
  91
  92   v8::Persistent<v8::FunctionTemplate> function_template_;
  93
  94   raw_ptr<v8::Isolate> isolate_;
  95
  96   base::WeakPtr<Client> client_;
  97
  98   scoped_refptr<base::SequencedTaskRunner> client_task_runner_;
  99
 100   base::WeakPtrFactory<PostMessageReceiver> weak_factory_{this};
 101 };
 102
 103 }  // namespace chrome_pdf
 104
 105 #endif  // PDF_POST_MESSAGE_RECEIVER_H_