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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      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 CONTENT_BROWSER_PLUGIN_LOADER_POSIX_H_
      6 #define CONTENT_BROWSER_PLUGIN_LOADER_POSIX_H_
      7 
      8 #include <vector>
      9 
     10 #include "base/basictypes.h"
     11 #include "base/compiler_specific.h"
     12 #include "base/memory/ref_counted.h"
     13 #include "base/time/time.h"
     14 #include "content/browser/plugin_service_impl.h"
     15 #include "content/public/browser/utility_process_host_client.h"
     16 #include "content/public/common/webplugininfo.h"
     17 #include "ipc/ipc_sender.h"
     18 
     19 namespace base {
     20 class MessageLoopProxy;
     21 }
     22 
     23 namespace content {
     24 class UtilityProcessHost;
     25 
     26 // This class is responsible for managing the out-of-process plugin loading on
     27 // POSIX systems. It primarily lives on the IO thread, but has a brief stay on
     28 // the FILE thread to iterate over plugin directories when it is first
     29 // constructed.
     30 //
     31 // The following is the algorithm used to load plugins:
     32 // 1. This asks the PluginList for the list of all potential plugins to attempt
     33 //    to load. This is referred to as the canonical list.
     34 // 2. The child process this hosts is forked and the canonical list is sent to
     35 //    it.
     36 // 3. The child process iterates over the canonical list, attempting to load
     37 //    each plugin in the order specified by the list. It sends an IPC message
     38 //    to the browser after each load, indicating success or failure. The two
     39 //    processes synchronize the position in the vector that will be used to
     40 //    attempt to load the next plugin.
     41 // 4. If the child dies during this process, the host forks another child and
     42 //    resumes loading at the position past the plugin that it just attempted to
     43 //    load, bypassing the problematic plugin.
     44 // 5. This algorithm continues until the canonical list has been walked to the
     45 //    end, after which the list of loaded plugins is set on the PluginList and
     46 //    the completion callback is run.
     47 class CONTENT_EXPORT PluginLoaderPosix
     48     : public NON_EXPORTED_BASE(UtilityProcessHostClient),
     49       public IPC::Sender {
     50  public:
     51   PluginLoaderPosix();
     52 
     53   // Must be called from the IO thread. The |callback| will be called on the IO
     54   // thread too.
     55   void GetPlugins(const PluginService::GetPluginsCallback& callback);
     56 
     57   // UtilityProcessHostClient:
     58   virtual void OnProcessCrashed(int exit_code) OVERRIDE;
     59   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
     60 
     61   // IPC::Sender:
     62   virtual bool Send(IPC::Message* msg) OVERRIDE;
     63 
     64  private:
     65   virtual ~PluginLoaderPosix();
     66 
     67   // Called on the FILE thread to get the list of plugin paths to probe.
     68   void GetPluginsToLoad();
     69 
     70   // Must be called on the IO thread.
     71   virtual void LoadPluginsInternal();
     72 
     73   // Called after plugin loading has finished, if we don't know whether the
     74   // plugin list has been invalidated in the mean time.
     75   void GetPluginsWrapper(
     76       const PluginService::GetPluginsCallback& callback,
     77       const std::vector<WebPluginInfo>& plugins_unused);
     78 
     79   // Message handlers.
     80   void OnPluginLoaded(uint32 index, const WebPluginInfo& plugin);
     81   void OnPluginLoadFailed(uint32 index, const base::FilePath& plugin_path);
     82 
     83   // Checks if the plugin path is an internal plugin, and, if it is, adds it to
     84   // |loaded_plugins_|.
     85   bool MaybeAddInternalPlugin(const base::FilePath& plugin_path);
     86 
     87   // Runs all the registered callbacks on each's target loop if the condition
     88   // for ending the load process is done (i.e. the |next_load_index_| is outside
     89   // the range of the |canonical_list_|).
     90   bool MaybeRunPendingCallbacks();
     91 
     92   // The process host for which this is a client.
     93   base::WeakPtr<UtilityProcessHost> process_host_;
     94 
     95   // A list of paths to plugins which will be loaded by the utility process, in
     96   // the order specified by this vector.
     97   std::vector<base::FilePath> canonical_list_;
     98 
     99   // The index in |canonical_list_| of the plugin that the child process will
    100   // attempt to load next.
    101   size_t next_load_index_;
    102 
    103   // Internal plugins that have been registered at the time of loading.
    104   std::vector<WebPluginInfo> internal_plugins_;
    105 
    106   // A vector of plugins that have been loaded successfully.
    107   std::vector<WebPluginInfo> loaded_plugins_;
    108 
    109   // The callback and message loop on which the callback will be run when the
    110   // plugin loading process has been completed.
    111   std::vector<PluginService::GetPluginsCallback> callbacks_;
    112 
    113   // The time at which plugin loading started.
    114   base::TimeTicks load_start_time_;
    115 
    116   friend class MockPluginLoaderPosix;
    117   DISALLOW_COPY_AND_ASSIGN(PluginLoaderPosix);
    118 };
    119 
    120 }  // namespace content
    121 
    122 #endif  // CONTENT_BROWSER_PLUGIN_LOADER_POSIX_H_
    123