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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 
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 gin {
14 class IsolateHolder;
15 }  // namespace gin
16 
17 namespace v8 {
18 class HeapStatistics;
19 class Isolate;
20 }  // namespace v8
21 
22 namespace net {
23 
24 // Implementation of ProxyResolver that uses V8 to evaluate PAC scripts.
25 //
26 // ----------------------------------------------------------------------------
27 // !!! Important note on threading model:
28 // ----------------------------------------------------------------------------
29 // There can be only one instance of V8 running at a time. To enforce this
30 // constraint, ProxyResolverV8 holds a v8::Locker during execution. Therefore
31 // it is OK to run multiple instances of ProxyResolverV8 on different threads,
32 // since only one will be running inside V8 at a time.
33 //
34 // It is important that *ALL* instances of V8 in the process be using
35 // v8::Locker. If not there can be race conditions between the non-locked V8
36 // instances and the locked V8 instances used by ProxyResolverV8 (assuming they
37 // run on different threads).
38 //
39 // This is the case with the V8 instance used by chromium's renderer -- it runs
40 // on a different thread from ProxyResolver (renderer thread vs PAC thread),
41 // and does not use locking since it expects to be alone.
42 class NET_EXPORT_PRIVATE ProxyResolverV8 : public ProxyResolver {
43  public:
44   // Interface for the javascript bindings.
45   class NET_EXPORT_PRIVATE JSBindings {
46    public:
47     enum ResolveDnsOperation {
48       DNS_RESOLVE,
49       DNS_RESOLVE_EX,
50       MY_IP_ADDRESS,
51       MY_IP_ADDRESS_EX,
52     };
53 
JSBindings()54     JSBindings() {}
55 
56     // Handler for "dnsResolve()", "dnsResolveEx()", "myIpAddress()",
57     // "myIpAddressEx()". Returns true on success and fills |*output| with the
58     // result. If |*terminate| is set to true, then the script execution will
59     // be aborted. Note that termination may not happen right away.
60     virtual bool ResolveDns(const std::string& host,
61                             ResolveDnsOperation op,
62                             std::string* output,
63                             bool* terminate) = 0;
64 
65     // Handler for "alert(message)"
66     virtual void Alert(const base::string16& message) = 0;
67 
68     // Handler for when an error is encountered. |line_number| may be -1
69     // if a line number is not applicable to this error.
70     virtual void OnError(int line_number, const base::string16& error) = 0;
71 
72    protected:
~JSBindings()73     virtual ~JSBindings() {}
74   };
75 
76   // Constructs a ProxyResolverV8.
77   ProxyResolverV8();
78 
79   virtual ~ProxyResolverV8();
80 
js_bindings()81   JSBindings* js_bindings() const { return js_bindings_; }
set_js_bindings(JSBindings * js_bindings)82   void set_js_bindings(JSBindings* js_bindings) { js_bindings_ = js_bindings; }
83 
84   // ProxyResolver implementation:
85   virtual int GetProxyForURL(const GURL& url,
86                              ProxyInfo* results,
87                              const net::CompletionCallback& /*callback*/,
88                              RequestHandle* /*request*/,
89                              const BoundNetLog& net_log) OVERRIDE;
90   virtual void CancelRequest(RequestHandle request) OVERRIDE;
91   virtual LoadState GetLoadState(RequestHandle request) const OVERRIDE;
92   virtual void CancelSetPacScript() OVERRIDE;
93   virtual int SetPacScript(
94       const scoped_refptr<ProxyResolverScriptData>& script_data,
95       const net::CompletionCallback& /*callback*/) OVERRIDE;
96 
97   // Create an isolate to use for the proxy resolver. If the embedder invokes
98   // this method multiple times, it must be invoked in a thread safe manner,
99   // e.g. always from the same thread.
100   static void EnsureIsolateCreated();
101 
102   static v8::Isolate* GetDefaultIsolate();
103 
104   // Get total/ued heap memory usage of all v8 instances used by the proxy
105   // resolver.
106   static size_t GetTotalHeapSize();
107   static size_t GetUsedHeapSize();
108 
109  private:
110   static gin::IsolateHolder* g_proxy_resolver_isolate_;
111 
112   // Context holds the Javascript state for the most recently loaded PAC
113   // script. It corresponds with the data from the last call to
114   // SetPacScript().
115   class Context;
116 
117   scoped_ptr<Context> context_;
118 
119   JSBindings* js_bindings_;
120 
121   DISALLOW_COPY_AND_ASSIGN(ProxyResolverV8);
122 };
123 
124 }  // namespace net
125 
126 #endif  // NET_PROXY_PROXY_RESOLVER_V8_H_
127