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// Copyright (c) 2008 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_USER_SCRIPT_MASTER_H_
#define CHROME_BROWSER_EXTENSIONS_USER_SCRIPT_MASTER_H_
#include "base/directory_watcher.h"
#include "base/file_path.h"
#include "base/message_loop.h"
#include "base/process.h"
#include "base/scoped_ptr.h"
#include "base/shared_memory.h"
#include "base/string_piece.h"
// Manages a segment of shared memory that contains the user scripts the user
// has installed. Lives on the UI thread.
class UserScriptMaster : public base::RefCounted<UserScriptMaster>,
public DirectoryWatcher::Delegate {
public:
// For testability, the constructor takes the MessageLoop to run the
// script-reloading worker on as well as the path the scripts live in.
// These are normally the file thread and a directory inside the profile.
UserScriptMaster(MessageLoop* worker, const FilePath& script_dir);
~UserScriptMaster();
// Gets the segment of shared memory for the scripts.
base::SharedMemory* GetSharedMemory() const {
return shared_memory_.get();
}
// Called by the script reloader when new scripts have been loaded.
void NewScriptsAvailable(base::SharedMemory* handle);
// Return true if we have any scripts ready.
bool ScriptsReady() const { return shared_memory_.get() != NULL; }
// Returns the path to the directory user scripts are stored in.
FilePath user_script_dir() const { return *user_script_dir_; }
private:
FRIEND_TEST(UserScriptMasterTest, Parse1);
FRIEND_TEST(UserScriptMasterTest, Parse2);
FRIEND_TEST(UserScriptMasterTest, Parse3);
// We reload user scripts on the file thread to prevent blocking the UI.
// ScriptReloader lives on the file thread and does the reload
// work, and then sends a message back to its master with a new SharedMemory*.
// ScriptReloader is the worker that manages running the script scan
// on the file thread. It must be created on, and its public API must only be
// called from, the master's thread.
class ScriptReloader
: public base::RefCounted<UserScriptMaster::ScriptReloader> {
public:
// Parses the includes out of |script| and returns them in |includes|.
static void ParseMetadataHeader(const StringPiece& script,
std::vector<std::string>* includes);
ScriptReloader(UserScriptMaster* master)
: master_(master), master_message_loop_(MessageLoop::current()) {}
// Start a scan for scripts.
// Will always send a message to the master upon completion.
void StartScan(MessageLoop* work_loop, const FilePath& script_dir);
// The master is going away; don't call it back.
void DisownMaster() {
master_ = NULL;
}
private:
// Where functions are run:
// master file
// StartScan -> RunScan
// GetNewScripts()
// ParseMetadataHeader()
// NotifyMaster <- RunScan
// Runs on the master thread.
// Notify the master that new scripts are available.
void NotifyMaster(base::SharedMemory* memory);
// Runs on the File thread.
// Scan the script directory for scripts, calling NotifyMaster when done.
// The path is intentionally passed by value so its lifetime isn't tied
// to the caller.
void RunScan(const FilePath script_dir);
// Runs on the File thread.
// Scan the script directory for scripts, returning either a
// new SharedMemory or NULL on error.
base::SharedMemory* GetNewScripts(const FilePath& script_dir);
// A pointer back to our master.
// May be NULL if DisownMaster() is called.
UserScriptMaster* master_;
// The message loop to call our master back on.
// Expected to always outlive us.
MessageLoop* master_message_loop_;
DISALLOW_COPY_AND_ASSIGN(ScriptReloader);
};
// DirectoryWatcher::Delegate implementation.
virtual void OnDirectoryChanged(const FilePath& path);
// Kicks off a process on the file thread to reload scripts from disk
// into a new chunk of shared memory and notify renderers.
void StartScan();
// The directory containing user scripts.
scoped_ptr<FilePath> user_script_dir_;
// The watcher watches the profile's user scripts directory for new scripts.
scoped_ptr<DirectoryWatcher> dir_watcher_;
// The MessageLoop that the scanner worker runs on.
// Typically the file thread; configurable for testing.
MessageLoop* worker_loop_;
// ScriptReloader (in another thread) reloads script off disk.
// We hang on to our pointer to know if we've already got one running.
scoped_refptr<ScriptReloader> script_reloader_;
// Contains the scripts that were found the last time scripts were updated.
scoped_ptr<base::SharedMemory> shared_memory_;
// If the script directory is modified while we're rescanning it, we note
// that we're currently mid-scan and then start over again once the scan
// finishes. This boolean tracks whether another scan is pending.
bool pending_scan_;
DISALLOW_COPY_AND_ASSIGN(UserScriptMaster);
};
#endif // CHROME_BROWSER_EXTENSIONS_USER_SCRIPT_MASTER_H_
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