net/proxy/proxy_resolver_v8.h

   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
   8 #include "base/compiler_specific.h"
   9 #include "base/memory/scoped_ptr.h"
  10 #include "net/base/net_export.h"
  11 #include "net/proxy/proxy_resolver.h"
  12
  13 namespace net {
  14
  15 class ProxyResolverJSBindings;
  16
  17 // Implementation of ProxyResolver that uses V8 to evaluate PAC scripts.
  18 //
  19 // ----------------------------------------------------------------------------
  20 // !!! Important note on threading model:
  21 // ----------------------------------------------------------------------------
  22 // There can be only one instance of V8 running at a time. To enforce this
  23 // constraint, ProxyResolverV8 holds a v8::Locker during execution. Therefore
  24 // it is OK to run multiple instances of ProxyResolverV8 on different threads,
  25 // since only one will be running inside V8 at a time.
  26 //
  27 // It is important that *ALL* instances of V8 in the process be using
  28 // v8::Locker. If not there can be race conditions between the non-locked V8
  29 // instances and the locked V8 instances used by ProxyResolverV8 (assuming they
  30 // run on different threads).
  31 //
  32 // This is the case with the V8 instance used by chromium's renderer -- it runs
  33 // on a different thread from ProxyResolver (renderer thread vs PAC thread),
  34 // and does not use locking since it expects to be alone.
  35 class NET_EXPORT_PRIVATE ProxyResolverV8 : public ProxyResolver {
  36  public:
  37   // Constructs a ProxyResolverV8 with custom bindings. ProxyResolverV8 takes
  38   // ownership of |custom_js_bindings| and deletes it when ProxyResolverV8
  39   // is destroyed.
  40   explicit ProxyResolverV8(ProxyResolverJSBindings* custom_js_bindings);
  41
  42   virtual ~ProxyResolverV8();
  43
  44   ProxyResolverJSBindings* js_bindings() const { return js_bindings_.get(); }
  45
  46   // ProxyResolver implementation:
  47   virtual int GetProxyForURL(const GURL& url,
  48                              ProxyInfo* results,
  49                              const net::CompletionCallback& /*callback*/,
  50                              RequestHandle* /*request*/,
  51                              const BoundNetLog& net_log) OVERRIDE;
  52   virtual void CancelRequest(RequestHandle request) OVERRIDE;
  53   virtual LoadState GetLoadState(RequestHandle request) const OVERRIDE;
  54   virtual LoadState GetLoadStateThreadSafe(
  55       RequestHandle request) const OVERRIDE;
  56   virtual void CancelSetPacScript() OVERRIDE;
  57   virtual void PurgeMemory() OVERRIDE;
  58   virtual void Shutdown() OVERRIDE;
  59   virtual int SetPacScript(
  60       const scoped_refptr<ProxyResolverScriptData>& script_data,
  61       const net::CompletionCallback& /*callback*/) OVERRIDE;
  62
  63  private:
  64   // Context holds the Javascript state for the most recently loaded PAC
  65   // script. It corresponds with the data from the last call to
  66   // SetPacScript().
  67   class Context;
  68   scoped_ptr<Context> context_;
  69
  70   scoped_ptr<ProxyResolverJSBindings> js_bindings_;
  71
  72   DISALLOW_COPY_AND_ASSIGN(ProxyResolverV8);
  73 };
  74
  75 }  // namespace net
  76
  77 #endif  // NET_PROXY_PROXY_RESOLVER_V8_H_