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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 
     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:
     73     virtual ~JSBindings() {}
     74   };
     75 
     76   // Constructs a ProxyResolverV8.
     77   ProxyResolverV8();
     78 
     79   virtual ~ProxyResolverV8();
     80 
     81   JSBindings* js_bindings() const { return 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