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// Copyright (c) 2009 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 CHROME_BROWSER_EXTENSIONS_EXTENSION_FUNCTION_H_
#define CHROME_BROWSER_EXTENSIONS_EXTENSION_FUNCTION_H_
#include <string>
#include "base/values.h"
#include "base/scoped_ptr.h"
#include "base/ref_counted.h"
#include "chrome/browser/extensions/extension_function_dispatcher.h"
class ExtensionFunctionDispatcher;
class Profile;
#define EXTENSION_FUNCTION_VALIDATE(test) do { \
if (!(test)) { \
bad_message_ = true; \
return false; \
} \
} while (0)
// Abstract base class for extension functions the ExtensionFunctionDispatcher
// knows how to dispatch to.
//
// TODO(aa): This will have to become reference counted when we introduce
// APIs that live beyond a single stack frame.
class ExtensionFunction : public base::RefCounted<ExtensionFunction> {
public:
ExtensionFunction() : request_id_(-1), has_callback_(false) {}
virtual ~ExtensionFunction() {}
// Specifies the name of the function.
virtual void SetName(const std::string& name) { }
// Specifies the raw arguments to the function, as a JSON-encoded string.
virtual void SetArgs(const std::string& args) = 0;
// Retrieves the results of the function as a JSON-encoded string (may
// be empty).
virtual const std::string GetResult() = 0;
// Retrieves any error string from the function.
virtual const std::string GetError() = 0;
void set_dispatcher_peer(ExtensionFunctionDispatcher::Peer* peer) {
peer_ = peer;
}
ExtensionFunctionDispatcher* dispatcher() {
return peer_->dispatcher_;
}
void set_request_id(int request_id) { request_id_ = request_id; }
int request_id() { return request_id_; }
void set_has_callback(bool has_callback) { has_callback_ = has_callback; }
bool has_callback() { return has_callback_; }
// Execute the API. Clients should call set_raw_args() and
// set_request_id() before calling this method. Derived classes should be
// ready to return raw_result() and error() before returning from this
// function.
virtual void Run() = 0;
protected:
// The peer to the dispatcher that will service this extension function call.
scoped_refptr<ExtensionFunctionDispatcher::Peer> peer_;
// Id of this request, used to map the response back to the caller.
int request_id_;
// True if the js caller provides a callback function to receive the response
// of this call.
bool has_callback_;
private:
DISALLOW_COPY_AND_ASSIGN(ExtensionFunction);
};
// Base class for an extension function that runs asynchronously *relative to
// the browser's UI thread*.
// Note that once Run() returns, dispatcher() can be NULL, so be sure to
// NULL-check.
// TODO(aa) Remove this extra level of inheritance once the browser stops
// parsing JSON (and instead uses custom serialization of Value objects).
class AsyncExtensionFunction : public ExtensionFunction {
public:
AsyncExtensionFunction() : args_(NULL), bad_message_(false) {}
virtual ~AsyncExtensionFunction() {}
virtual void SetArgs(const std::string& args);
virtual const std::string GetResult();
virtual const std::string GetError() { return error_; }
virtual void Run() = 0;
protected:
void SendResponse(bool success);
// Note: After Run() returns, dispatcher() can be NULL. Since these getters
// rely on dispatcher(), make sure it is valid before using them.
std::string extension_id();
Profile* profile();
// The arguments to the API. Only non-null if argument were specified.
Value* args_;
// The result of the API. This should be populated by the derived class before
// Run() returns.
scoped_ptr<Value> result_;
// Any detailed error from the API. This should be populated by the derived
// class before Run() returns.
std::string error_;
// Any class that gets a malformed message should set this to true before
// returning. The calling renderer process will be killed.
bool bad_message_;
private:
DISALLOW_COPY_AND_ASSIGN(AsyncExtensionFunction);
};
// A SyncExtensionFunction is an ExtensionFunction that runs synchronously
// *relative to the browser's UI thread*. Note that this has nothing to do with
// running synchronously relative to the extension process. From the extension
// process's point of view, the function is still asynchronous.
//
// This kind of function is convenient for implementing simple APIs that just
// need to interact with things on the browser UI thread.
class SyncExtensionFunction : public AsyncExtensionFunction {
public:
SyncExtensionFunction() {}
// Derived classes should implement this method to do their work and return
// success/failure.
virtual bool RunImpl() = 0;
virtual void Run() {
SendResponse(RunImpl());
}
private:
DISALLOW_COPY_AND_ASSIGN(SyncExtensionFunction);
};
#endif // CHROME_BROWSER_EXTENSIONS_EXTENSION_FUNCTION_H_
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