chromium/src/third_party/blink/renderer/bindings/core/v8/script_function.h

/*
 * Copyright (C) 2013 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions are
 * met:
 *
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 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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#ifndef THIRD_PARTY_BLINK_RENDERER_BINDINGS_CORE_V8_SCRIPT_FUNCTION_H_
#define THIRD_PARTY_BLINK_RENDERER_BINDINGS_CORE_V8_SCRIPT_FUNCTION_H_

#include "third_party/blink/renderer/bindings/core/v8/custom_wrappable_adapter.h"
#include "third_party/blink/renderer/bindings/core/v8/script_value.h"
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/platform/bindings/script_state.h"
#include "third_party/blink/renderer/platform/bindings/trace_wrapper_v8_reference.h"
#include "third_party/blink/renderer/platform/heap/handle.h"
#include "v8/include/v8.h"

namespace blink {

// DEPRECATED: Use NewScriptFunction.
class CORE_EXPORT ScriptFunction : public CustomWrappableAdapter {
 public:
  ~ScriptFunction() override = default;

  void Trace(Visitor*) const override;

  const char* NameInHeapSnapshot() const override { return "ScriptFunction"; }

 protected:
  explicit ScriptFunction(ScriptState* script_state)
      : script_state_(script_state) {}

  ScriptState* GetScriptState() const { return script_state_; }

  // It is not usually necessary to set |length| unless the function is exposed
  // to JavaScript.
  v8::Local<v8::Function> BindToV8Function(int length = 0);

 private:
  // Subclasses should implement one of Call() or CallRaw(). Most will implement
  // Call().
  virtual ScriptValue Call(ScriptValue);

  // To support more than one argument, or for low-level access to the V8 API,
  // implement CallRaw(). The default implementation delegates to Call().
  virtual void CallRaw(const v8::FunctionCallbackInfo<v8::Value>&);

  static void CallCallback(const v8::FunctionCallbackInfo<v8::Value>&);

  Member<ScriptState> script_state_;
#if DCHECK_IS_ON()
  // BindToV8Function() must not be called twice.
  bool bind_to_v8_function_already_called_ = false;
#endif
};

// A `NewScriptFunction` represents a function that can be called from scripts.
// You can define a subclass of `Callable` and put arbitrary logic by
// overriding `Call` or `CallRaw` methods.
class CORE_EXPORT NewScriptFunction final
    : public GarbageCollected<NewScriptFunction> {
 public:
  class CORE_EXPORT Callable : public GarbageCollected<Callable> {
   public:
    virtual ~Callable() = default;

    // Subclasses should implement one of Call() or CallRaw(). Most will
    // implement Call().
    virtual ScriptValue Call(ScriptState*, ScriptValue);

    // To support more than one argument, or for low-level access to the V8 API,
    // implement CallRaw(). The default implementation delegates to Call().
    virtual void CallRaw(ScriptState*,
                         const v8::FunctionCallbackInfo<v8::Value>&);

    // The length of the aosociated JavaScript function. Implement this only
    // when the function is exposed to scripts.
    virtual int Length() const { return 0; }

    virtual void Trace(Visitor* visitor) const {}
  };

  // Represents a function that returns a value given to the constructor.
  class Constant final : public Callable {
   public:
    explicit Constant(ScriptValue value) : value_(value) {}
    void Trace(Visitor* visitor) const override {
      visitor->Trace(value_);
      Callable::Trace(visitor);
    }
    ScriptValue Call(ScriptState*, ScriptValue) override { return value_; }

   private:
    const ScriptValue value_;
  };

  NewScriptFunction(ScriptState* script_state, Callable* callable)
      : script_state_(script_state),
        function_(script_state->GetIsolate(),
                  BindToV8Function(script_state, callable)) {}

  void Trace(Visitor* visitor) const {
    visitor->Trace(script_state_);
    visitor->Trace(function_);
  }

  v8::Local<v8::Function> V8Function() {
    return function_.NewLocal(script_state_->GetIsolate());
  }

 private:
  static v8::Local<v8::Function> BindToV8Function(ScriptState*, Callable*);
  static void CallCallback(const v8::FunctionCallbackInfo<v8::Value>&);

  Member<ScriptState> script_state_;
  TraceWrapperV8Reference<v8::Function> function_;
};

}  // namespace blink

#endif