Revert 85646 - Adds support for the DHCP portion of the WPAD (proxy auto-discovery) protocol.

net/proxy/dhcp_proxy_script_adapter_fetcher_win.h

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef NET_PROXY_DHCP_SCRIPT_ADAPTER_FETCHER_WIN_H_
-#define NET_PROXY_DHCP_SCRIPT_ADAPTER_FETCHER_WIN_H_
-#pragma once
-
-#include "base/memory/ref_counted.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/memory/weak_ptr.h"
-#include "base/string16.h"
-#include "base/threading/non_thread_safe.h"
-#include "base/timer.h"
-#include "net/base/completion_callback.h"
-#include "googleurl/src/gurl.h"
-
-namespace base {
-class MessageLoopProxy;
-}
-
-namespace net {
-
-class ProxyScriptFetcher;
-class URLRequestContext;
-
-// For a given adapter, this class takes care of first doing a DHCP lookup
-// to get the PAC URL, then if there is one, trying to fetch it.
-class DhcpProxyScriptAdapterFetcher
-    : public base::SupportsWeakPtr<DhcpProxyScriptAdapterFetcher>,
-      public base::NonThreadSafe {
- public:
-  // |url_request_context| must outlive DhcpProxyScriptAdapterFetcher.
-  explicit DhcpProxyScriptAdapterFetcher(
-      URLRequestContext* url_request_context);
-  virtual ~DhcpProxyScriptAdapterFetcher();
-
-  // Starts a fetch.  On completion (but not cancellation), |callback|
-  // will be invoked with the network error indicating success or failure
-  // of fetching a DHCP-configured PAC file on this adapter.
-  //
-  // On completion, results can be obtained via |GetPacScript()|, |GetPacURL()|.
-  //
-  // You may only call Fetch() once on a given instance of
-  // DhcpProxyScriptAdapterFetcher.
-  virtual void Fetch(const std::string& adapter_name,
-                     CompletionCallback* callback);
-
-  // Cancels the fetch on this adapter.
-  virtual void Cancel();
-
-  // Returns true if in the FINISH state (not CANCEL).
-  virtual bool DidFinish() const;
-
-  // Returns the network error indicating the result of the fetch. Will
-  // return IO_PENDING until the fetch is complete or cancelled. This is
-  // the same network error passed to the |callback| provided to |Fetch()|.
-  virtual int GetResult() const;
-
-  // Returns the contents of the PAC file retrieved.  Only valid if
-  // |IsComplete()| is true.  Returns the empty string if |GetResult()|
-  // returns anything other than OK.
-  virtual string16 GetPacScript() const;
-
-  // Returns the PAC URL retrieved from DHCP.  Only guaranteed to be
-  // valid if |IsComplete()| is true.  Returns an empty URL if no URL was
-  // configured in DHCP.  May return a valid URL even if |result()| does
-  // not return OK (this would indicate that we found a URL configured in
-  // DHCP but failed to download it).
-  virtual GURL GetPacURL() const;
-
-  // Returns the PAC URL configured in DHCP for the given |adapter_name|, or
-  // the empty string if none is configured.
-  //
-  // This function executes synchronously due to limitations of the Windows
-  // DHCP client API.
-  static std::string GetPacURLFromDhcp(const std::string& adapter_name);
-
- protected:
-  // This inner class is used to encapsulate the worker thread, which has
-  // only a weak reference back to the main object, so that the main object
-  // can be destroyed before the thread ends.  This also keeps the main
-  // object completely thread safe and allows it to be non-refcounted.
-  class WorkerThread : public base::RefCountedThreadSafe<WorkerThread> {
-   public:
-    // Creates and initializes (but does not start) the worker thread.
-    explicit WorkerThread(
-        const base::WeakPtr<DhcpProxyScriptAdapterFetcher>& owner);
-    virtual ~WorkerThread();
-
-    // Starts the worker thread, fetching information for |adapter_name| using
-    // |get_pac_from_url_func|.
-    void Start(const std::string& adapter_name);
-
-   protected:
-    // Virtual method introduced to allow unit testing.
-    virtual std::string ImplGetPacURLFromDhcp(const std::string& adapter_name);
-
-   private:
-    // This is the method that runs on the worker thread.
-    void ThreadFunc(const std::string& adapter_name);
-
-    // Callback for the above; this executes back on the main thread,
-    // not the worker thread.
-    void OnThreadDone(const std::string& url);
-
-    // All work except ThreadFunc and (sometimes) destruction should occur
-    // on the thread that constructs the object.
-    base::ThreadChecker thread_checker_;
-
-    // May only be accessed on the thread that constructs the object.
-    base::WeakPtr<DhcpProxyScriptAdapterFetcher> owner_;
-
-    // Used by worker thread to post a message back to the original
-    // thread.  Fine to use a proxy since in the case where the original
-    // thread has gone away, that would mean the |owner_| object is gone
-    // anyway, so there is nobody to receive the result.
-    scoped_refptr<base::MessageLoopProxy> origin_loop_;
-
-    DISALLOW_COPY_AND_ASSIGN(WorkerThread);
-  };
-
-  // Event/state transition handlers
-  void OnQueryDhcpDone(const std::string& url);
-  void OnTimeout();
-  void OnFetcherDone(int result);
-  void TransitionToFinish();
-
-  // Virtual methods introduced to allow unit testing.
-  virtual ProxyScriptFetcher* ImplCreateScriptFetcher();
-  virtual WorkerThread* ImplCreateWorkerThread(
-      const base::WeakPtr<DhcpProxyScriptAdapterFetcher>& owner);
-  virtual base::TimeDelta ImplGetTimeout() const;
-
-  // This is the state machine for fetching from a given adapter.
-  //
-  // The state machine goes from START->WAIT_DHCP when it starts
-  // a worker thread to fetch the PAC URL from DHCP.
-  //
-  // In state WAIT_DHCP, if the DHCP query finishes and has no URL, it
-  // moves to state FINISH.  If there is a URL, it starts a
-  // ProxyScriptFetcher to fetch it and moves to state WAIT_URL.
-  //
-  // It goes from WAIT_URL->FINISH when the ProxyScriptFetcher completes.
-  //
-  // In state FINISH, completion is indicated to the outer class, with
-  // the results of the fetch if a PAC script was successfully fetched.
-  //
-  // In state WAIT_DHCP, our timeout occurring can push us to FINISH.
-  //
-  // In any state except FINISH, a call to Cancel() will move to state
-  // CANCEL and cause all outstanding work to be cancelled or its
-  // results ignored when available.
-  enum State {
-    STATE_START,
-    STATE_WAIT_DHCP,
-    STATE_WAIT_URL,
-    STATE_FINISH,
-    STATE_CANCEL,
-  };
-
-  // Current state of this state machine.
-  State state_;
-
-  // A network error indicating result of operation.
-  int result_;
-
-  // Empty string or the PAC script downloaded.
-  string16 pac_script_;
-
-  // Empty URL or the PAC URL configured in DHCP.
-  GURL pac_url_;
-
-  // Callback to let our client know we're done. Invalid in states
-  // START, FINISH and CANCEL.
-  CompletionCallback* callback_;
-
-  // Container for our worker thread. NULL if not currently running.
-  scoped_refptr<WorkerThread> worker_thread_;
-
-  // Fetcher to retrieve PAC files once URL is known.
-  scoped_ptr<ProxyScriptFetcher> script_fetcher_;
-
-  // Callback from the script fetcher.
-  CompletionCallbackImpl<DhcpProxyScriptAdapterFetcher>
-      script_fetcher_callback_;
-
-  // Implements a timeout on the call to the Win32 DHCP API.
-  base::OneShotTimer<DhcpProxyScriptAdapterFetcher> wait_timer_;
-
-  scoped_refptr<URLRequestContext> url_request_context_;
-
-  DISALLOW_IMPLICIT_CONSTRUCTORS(DhcpProxyScriptAdapterFetcher);
-};
-
-}  // namespace net
-
-#endif  // NET_PROXY_DHCP_SCRIPT_ADAPTER_FETCHER_WIN_H_