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      1 // Copyright (c) 2011 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 NET_PROXY_PROXY_RESOLVER_V8_H_
      6 #define NET_PROXY_PROXY_RESOLVER_V8_H_
      7 #pragma once
      8 
      9 #include "base/memory/scoped_ptr.h"
     10 #include "net/proxy/proxy_resolver.h"
     11 
     12 namespace net {
     13 
     14 class ProxyResolverJSBindings;
     15 
     16 // Implementation of ProxyResolver that uses V8 to evaluate PAC scripts.
     17 //
     18 // ----------------------------------------------------------------------------
     19 // !!! Important note on threading model:
     20 // ----------------------------------------------------------------------------
     21 // There can be only one instance of V8 running at a time. To enforce this
     22 // constraint, ProxyResolverV8 holds a v8::Locker during execution. Therefore
     23 // it is OK to run multiple instances of ProxyResolverV8 on different threads,
     24 // since only one will be running inside V8 at a time.
     25 //
     26 // It is important that *ALL* instances of V8 in the process be using
     27 // v8::Locker. If not there can be race conditions beween the non-locked V8
     28 // instances and the locked V8 instances used by ProxyResolverV8 (assuming they
     29 // run on different threads).
     30 //
     31 // This is the case with the V8 instance used by chromium's renderer -- it runs
     32 // on a different thread from ProxyResolver (renderer thread vs PAC thread),
     33 // and does not use locking since it expects to be alone.
     34 class ProxyResolverV8 : public ProxyResolver {
     35  public:
     36   // Constructs a ProxyResolverV8 with custom bindings. ProxyResolverV8 takes
     37   // ownership of |custom_js_bindings| and deletes it when ProxyResolverV8
     38   // is destroyed.
     39   explicit ProxyResolverV8(ProxyResolverJSBindings* custom_js_bindings);
     40 
     41   virtual ~ProxyResolverV8();
     42 
     43   ProxyResolverJSBindings* js_bindings() const { return js_bindings_.get(); }
     44 
     45   // ProxyResolver implementation:
     46   virtual int GetProxyForURL(const GURL& url,
     47                              ProxyInfo* results,
     48                              CompletionCallback* /*callback*/,
     49                              RequestHandle* /*request*/,
     50                              const BoundNetLog& net_log);
     51   virtual void CancelRequest(RequestHandle request);
     52   virtual void CancelSetPacScript();
     53   virtual void PurgeMemory();
     54   virtual void Shutdown();
     55   virtual int SetPacScript(
     56       const scoped_refptr<ProxyResolverScriptData>& script_data,
     57       CompletionCallback* /*callback*/);
     58 
     59  private:
     60   // Context holds the Javascript state for the most recently loaded PAC
     61   // script. It corresponds with the data from the last call to
     62   // SetPacScript().
     63   class Context;
     64   scoped_ptr<Context> context_;
     65 
     66   scoped_ptr<ProxyResolverJSBindings> js_bindings_;
     67 
     68   DISALLOW_COPY_AND_ASSIGN(ProxyResolverV8);
     69 };
     70 
     71 }  // namespace net
     72 
     73 #endif  // NET_PROXY_PROXY_RESOLVER_V8_H_
     74