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// Copyright 2014 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 EXTENSIONS_BROWSER_USER_SCRIPT_LOADER_H_
#define EXTENSIONS_BROWSER_USER_SCRIPT_LOADER_H_
#include <map>
#include <set>
#include "base/compiler_specific.h"
#include "base/macros.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/shared_memory.h"
#include "base/memory/weak_ptr.h"
#include "base/observer_list.h"
#include "base/scoped_observer.h"
#include "content/public/browser/notification_observer.h"
#include "content/public/browser/notification_registrar.h"
#include "extensions/common/host_id.h"
#include "extensions/common/user_script.h"
namespace base {
class SharedMemory;
}
namespace content {
class BrowserContext;
class RenderProcessHost;
}
namespace extensions {
// Manages one "logical unit" of user scripts in shared memory by constructing a
// new shared memory region when the set of scripts changes. Also notifies
// renderers of new shared memory region when new renderers appear, or when
// script reloading completes. Script loading lives on the UI thread. Instances
// of this class are embedded within classes with names ending in
// UserScriptMaster. These "master" classes implement the strategy for which
// scripts to load/unload on this logical unit of scripts.
class UserScriptLoader : public content::NotificationObserver {
public:
using LoadScriptsCallback =
base::Callback<void(scoped_ptr<UserScriptList>,
scoped_ptr<base::SharedMemory>)>;
class Observer {
public:
virtual void OnScriptsLoaded(UserScriptLoader* loader) = 0;
virtual void OnUserScriptLoaderDestroyed(UserScriptLoader* loader) = 0;
};
// Parses the includes out of |script| and returns them in |includes|.
static bool ParseMetadataHeader(const base::StringPiece& script_text,
UserScript* script);
UserScriptLoader(content::BrowserContext* browser_context,
const HostID& host_id);
~UserScriptLoader() override;
// Add |scripts| to the set of scripts managed by this loader.
void AddScripts(const std::set<UserScript>& scripts);
// Add |scripts| to the set of scripts managed by this loader.
// The fetch of the content of the script starts URL request
// to the associated render specified by
// |render_process_id, render_view_id|.
// TODO(hanxi): The renderer information doesn't really belong in this base
// class, but it's not an easy fix.
virtual void AddScripts(const std::set<UserScript>& scripts,
int render_process_id,
int render_view_id);
// Remove |scripts| from the set of scripts managed by this loader.
void RemoveScripts(const std::set<UserScript>& scripts);
// Clears the set of scripts managed by this loader.
void ClearScripts();
// Initiates procedure to start loading scripts on the file thread.
void StartLoad();
// Returns true if we have any scripts ready.
bool scripts_ready() const { return shared_memory_.get() != NULL; }
// Pickle user scripts and return pointer to the shared memory.
static scoped_ptr<base::SharedMemory> Serialize(
const extensions::UserScriptList& scripts);
// Adds or removes observers.
void AddObserver(Observer* observer);
void RemoveObserver(Observer* observer);
protected:
// Allows the derived classes have different ways to load user scripts.
virtual void LoadScripts(scoped_ptr<UserScriptList> user_scripts,
const std::set<HostID>& changed_hosts,
const std::set<int>& added_script_ids,
LoadScriptsCallback callback) = 0;
// Sets the flag if the initial set of hosts has finished loading; if it's
// set to be true, calls AttempLoad() to bootstrap.
void SetReady(bool ready);
content::BrowserContext* browser_context() const { return browser_context_; }
const HostID& host_id() const { return host_id_; }
private:
// content::NotificationObserver implementation.
void Observe(int type,
const content::NotificationSource& source,
const content::NotificationDetails& details) override;
// Returns whether or not it is possible that calls to AddScripts(),
// RemoveScripts(), and/or ClearScripts() have caused any real change in the
// set of scripts to be loaded.
bool ScriptsMayHaveChanged() const;
// Attempts to initiate a load.
void AttemptLoad();
// Called once we have finished loading the scripts on the file thread.
void OnScriptsLoaded(scoped_ptr<UserScriptList> user_scripts,
scoped_ptr<base::SharedMemory> shared_memory);
// Sends the renderer process a new set of user scripts. If
// |changed_hosts| is not empty, this signals that only the scripts from
// those hosts should be updated. Otherwise, all hosts will be
// updated.
void SendUpdate(content::RenderProcessHost* process,
base::SharedMemory* shared_memory,
const std::set<HostID>& changed_hosts);
bool is_loading() const {
// Ownership of |user_scripts_| is passed to the file thread when loading.
return user_scripts_.get() == NULL;
}
// Manages our notification registrations.
content::NotificationRegistrar registrar_;
// Contains the scripts that were found the last time scripts were updated.
scoped_ptr<base::SharedMemory> shared_memory_;
// List of scripts from currently-installed extensions we should load.
scoped_ptr<UserScriptList> user_scripts_;
// The mutually-exclusive sets of scripts that were added or removed since the
// last script load.
std::set<UserScript> added_scripts_;
std::set<UserScript> removed_scripts_;
// Indicates whether the the collection of scripts should be cleared before
// additions and removals on the next script load.
bool clear_scripts_;
// The IDs of the extensions which changed in the last update sent to the
// renderer.
std::set<HostID> changed_hosts_;
// If the initial set of hosts has finished loading.
bool ready_;
// If list of user scripts is modified while we're loading it, we note
// that we're currently mid-load and then start over again once the load
// finishes. This boolean tracks whether another load is pending.
bool pending_load_;
// The browser_context for which the scripts managed here are installed.
content::BrowserContext* browser_context_;
// ID of the host that owns these scripts, if any. This is only set to a
// non-empty value for declarative user script shared memory regions.
HostID host_id_;
// The associated observers.
base::ObserverList<Observer> observers_;
base::WeakPtrFactory<UserScriptLoader> weak_factory_;
DISALLOW_COPY_AND_ASSIGN(UserScriptLoader);
};
} // namespace extensions
#endif // EXTENSIONS_BROWSER_USER_SCRIPT_LOADER_H_
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