[email protected] | 72b4a77 | 2010-07-14 01:29:30 | [diff] [blame] | 1 | // Copyright (c) 2010 The Chromium Authors. All rights reserved. |
[email protected] | 61b84d5 | 2010-07-09 03:32:00 | [diff] [blame] | 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 NET_PROXY_MULTI_THREADED_PROXY_RESOLVER_H_ |
| 6 | #define NET_PROXY_MULTI_THREADED_PROXY_RESOLVER_H_ |
[email protected] | 32b76ef | 2010-07-26 23:08:24 | [diff] [blame^] | 7 | #pragma once |
[email protected] | 61b84d5 | 2010-07-09 03:32:00 | [diff] [blame] | 8 | |
| 9 | #include <deque> |
| 10 | #include <string> |
| 11 | #include <vector> |
| 12 | |
| 13 | #include "base/basictypes.h" |
| 14 | #include "base/non_thread_safe.h" |
| 15 | #include "base/ref_counted.h" |
| 16 | #include "base/scoped_ptr.h" |
| 17 | #include "net/proxy/proxy_resolver.h" |
| 18 | |
| 19 | namespace base { |
| 20 | class Thread; |
| 21 | } // namespace base |
| 22 | |
| 23 | namespace net { |
| 24 | |
| 25 | // ProxyResolverFactory is an interface for creating ProxyResolver instances. |
| 26 | class ProxyResolverFactory { |
| 27 | public: |
| 28 | explicit ProxyResolverFactory(bool resolvers_expect_pac_bytes) |
| 29 | : resolvers_expect_pac_bytes_(resolvers_expect_pac_bytes) {} |
| 30 | |
| 31 | virtual ~ProxyResolverFactory() {} |
| 32 | |
| 33 | // Creates a new ProxyResolver. The caller is responsible for freeing this |
| 34 | // object. |
| 35 | virtual ProxyResolver* CreateProxyResolver() = 0; |
| 36 | |
| 37 | bool resolvers_expect_pac_bytes() const { |
| 38 | return resolvers_expect_pac_bytes_; |
| 39 | } |
| 40 | |
| 41 | private: |
| 42 | bool resolvers_expect_pac_bytes_; |
| 43 | DISALLOW_COPY_AND_ASSIGN(ProxyResolverFactory); |
| 44 | }; |
| 45 | |
| 46 | // MultiThreadedProxyResolver is a ProxyResolver implementation that runs |
| 47 | // synchronous ProxyResolver implementations on worker threads. |
| 48 | // |
| 49 | // Threads are created lazily on demand, up to a maximum total. The advantage |
| 50 | // of having a pool of threads, is faster performance. In particular, being |
| 51 | // able to keep servicing PAC requests even if one blocks its execution. |
| 52 | // |
| 53 | // During initialization (SetPacScript), a single thread is spun up to test |
| 54 | // the script. If this succeeds, we cache the input script, and will re-use |
| 55 | // this to lazily provision any new threads as needed. |
| 56 | // |
| 57 | // For each new thread that we spawn, a corresponding new ProxyResolver is |
| 58 | // created using ProxyResolverFactory. |
| 59 | // |
| 60 | // Because we are creating multiple ProxyResolver instances, this means we |
| 61 | // are duplicating script contexts for what is ordinarily seen as being a |
| 62 | // single script. This can affect compatibility on some classes of PAC |
| 63 | // script: |
| 64 | // |
| 65 | // (a) Scripts whose initialization has external dependencies on network or |
| 66 | // time may end up successfully initializing on some threads, but not |
| 67 | // others. So depending on what thread services the request, the result |
| 68 | // may jump between several possibilities. |
| 69 | // |
| 70 | // (b) Scripts whose FindProxyForURL() depends on side-effects may now |
| 71 | // work differently. For example, a PAC script which was incrementing |
| 72 | // a global counter and using that to make a decision. In the |
| 73 | // multi-threaded model, each thread may have a different value for this |
| 74 | // counter, so it won't globally be seen as monotonically increasing! |
| 75 | class MultiThreadedProxyResolver : public ProxyResolver, public NonThreadSafe { |
| 76 | public: |
| 77 | // Creates an asynchronous ProxyResolver that runs requests on up to |
| 78 | // |max_num_threads|. |
| 79 | // |
| 80 | // For each thread that is created, an accompanying synchronous ProxyResolver |
| 81 | // will be provisioned using |resolver_factory|. All methods on these |
| 82 | // ProxyResolvers will be called on the one thread, with the exception of |
| 83 | // ProxyResolver::Shutdown() which will be called from the origin thread |
| 84 | // prior to destruction. |
| 85 | // |
| 86 | // The constructor takes ownership of |resolver_factory|. |
| 87 | MultiThreadedProxyResolver(ProxyResolverFactory* resolver_factory, |
| 88 | size_t max_num_threads); |
| 89 | |
| 90 | virtual ~MultiThreadedProxyResolver(); |
| 91 | |
| 92 | // ProxyResolver implementation: |
| 93 | virtual int GetProxyForURL(const GURL& url, |
| 94 | ProxyInfo* results, |
| 95 | CompletionCallback* callback, |
| 96 | RequestHandle* request, |
| 97 | const BoundNetLog& net_log); |
| 98 | virtual void CancelRequest(RequestHandle request); |
| 99 | virtual void CancelSetPacScript(); |
| 100 | virtual void PurgeMemory(); |
[email protected] | 2447640 | 2010-07-20 20:55:17 | [diff] [blame] | 101 | virtual int SetPacScript( |
| 102 | const scoped_refptr<ProxyResolverScriptData>& script_data, |
| 103 | CompletionCallback* callback); |
[email protected] | 61b84d5 | 2010-07-09 03:32:00 | [diff] [blame] | 104 | |
| 105 | private: |
| 106 | class Executor; |
| 107 | class Job; |
| 108 | class SetPacScriptJob; |
| 109 | class GetProxyForURLJob; |
| 110 | // FIFO queue of pending jobs waiting to be started. |
| 111 | // TODO(eroman): Make this priority queue. |
| 112 | typedef std::deque<scoped_refptr<Job> > PendingJobsQueue; |
| 113 | typedef std::vector<scoped_refptr<Executor> > ExecutorList; |
| 114 | |
[email protected] | 61b84d5 | 2010-07-09 03:32:00 | [diff] [blame] | 115 | // Asserts that there are no outstanding user-initiated jobs on any of the |
| 116 | // worker threads. |
| 117 | void CheckNoOutstandingUserRequests() const; |
| 118 | |
| 119 | // Stops and deletes all of the worker threads. |
| 120 | void ReleaseAllExecutors(); |
| 121 | |
| 122 | // Returns an idle worker thread which is ready to receive GetProxyForURL() |
| 123 | // requests. If all threads are occupied, returns NULL. |
| 124 | Executor* FindIdleExecutor(); |
| 125 | |
| 126 | // Creates a new worker thread, and appends it to |executors_|. |
| 127 | Executor* AddNewExecutor(); |
| 128 | |
| 129 | // Starts the next job from |pending_jobs_| if possible. |
| 130 | void OnExecutorReady(Executor* executor); |
| 131 | |
| 132 | const scoped_ptr<ProxyResolverFactory> resolver_factory_; |
| 133 | const size_t max_num_threads_; |
| 134 | PendingJobsQueue pending_jobs_; |
| 135 | ExecutorList executors_; |
[email protected] | 2447640 | 2010-07-20 20:55:17 | [diff] [blame] | 136 | scoped_refptr<ProxyResolverScriptData> current_script_data_; |
[email protected] | 61b84d5 | 2010-07-09 03:32:00 | [diff] [blame] | 137 | }; |
| 138 | |
| 139 | } // namespace net |
| 140 | |
| 141 | #endif // NET_PROXY_MULTI_THREADED_PROXY_RESOLVER_H_ |