Adds a modified copy of talk/base to webrtc/base. It is the first step in migrating talk/base to webrtc/base.

BUG=N/A
R=andrew@webrtc.org, wu@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/12199004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6107 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/base/win32toolhelp.h

@@ -0,0 +1,172 @@
+/*
+ *  Copyright 2010 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#ifndef WEBRTC_BASE_WIN32TOOLHELP_H_
+#define WEBRTC_BASE_WIN32TOOLHELP_H_
+
+#if !defined(WEBRTC_WIN)
+#error WEBRTC_WIN Only
+#endif
+
+#include "webrtc/base/win32.h"
+
+// Should be included first, but that causes redefinitions.
+#include <tlhelp32.h>
+
+#include "webrtc/base/constructormagic.h"
+
+namespace rtc {
+
+// The toolhelp api used to enumerate processes and their modules
+// on Windows is very repetetive and clunky to use. This little
+// template wraps it to make it a little more programmer friendly.
+//
+// Traits: Traits type that adapts the enumerator to the corresponding
+//         win32 toolhelp api. Each traits class need to:
+//         - define the type of the enumerated data as a public symbol Type
+//
+//         - implement bool First(HANDLE, T*) normally calls a
+//           Xxxx32First method in the toolhelp API. Ex Process32First(...)
+//
+//         - implement bool Next(HANDLE, T*) normally calls a
+//           Xxxx32Next method in the toolhelp API. Ex Process32Next(...)
+//
+//         - implement bool CloseHandle(HANDLE)
+//
+template<typename Traits>
+class ToolhelpEnumeratorBase {
+ public:
+  ToolhelpEnumeratorBase(HANDLE snapshot)
+      : snapshot_(snapshot), broken_(false), first_(true) {
+
+    // Clear out the Traits::Type structure instance.
+    Zero(&current_);
+  }
+
+  virtual ~ToolhelpEnumeratorBase() {
+    Close();
+  }
+
+  // Moves forward to the next object using the First and Next
+  // pointers. If either First or Next ever indicates an failure
+  // all subsequent calls to this method will fail; the enumerator
+  // object is considered broken.
+  bool Next() {
+    if (!Valid()) {
+      return false;
+    }
+
+    // Move the iteration forward.
+    current_.dwSize = sizeof(typename Traits::Type);
+    bool incr_ok = false;
+    if (first_) {
+      incr_ok = Traits::First(snapshot_, &current_);
+      first_ = false;
+    } else {
+      incr_ok = Traits::Next(snapshot_, &current_);
+    }
+
+    if (!incr_ok) {
+      Zero(&current_);
+      broken_ = true;
+    }
+
+    return incr_ok;
+  }
+
+  const typename Traits::Type& current() const {
+    return current_;
+  }
+
+  void Close() {
+    if (snapshot_ != INVALID_HANDLE_VALUE) {
+      Traits::CloseHandle(snapshot_);
+      snapshot_ = INVALID_HANDLE_VALUE;
+    }
+  }
+
+ private:
+  // Checks the state of the snapshot handle.
+  bool Valid() {
+    return snapshot_ != INVALID_HANDLE_VALUE && !broken_;
+  }
+
+  static void Zero(typename Traits::Type* buff) {
+    ZeroMemory(buff, sizeof(typename Traits::Type));
+  }
+
+  HANDLE snapshot_;
+  typename Traits::Type current_;
+  bool broken_;
+  bool first_;
+};
+
+class ToolhelpTraits {
+ public:
+  static HANDLE CreateSnapshot(uint32 flags, uint32 process_id) {
+    return CreateToolhelp32Snapshot(flags, process_id);
+  }
+
+  static bool CloseHandle(HANDLE handle) {
+    return ::CloseHandle(handle) == TRUE;
+  }
+};
+
+class ToolhelpProcessTraits : public ToolhelpTraits {
+ public:
+  typedef PROCESSENTRY32 Type;
+
+  static bool First(HANDLE handle, Type* t) {
+    return ::Process32First(handle, t) == TRUE;
+  }
+
+  static bool Next(HANDLE handle, Type* t) {
+    return ::Process32Next(handle, t) == TRUE;
+  }
+};
+
+class ProcessEnumerator : public ToolhelpEnumeratorBase<ToolhelpProcessTraits> {
+ public:
+  ProcessEnumerator()
+      : ToolhelpEnumeratorBase(
+           ToolhelpProcessTraits::CreateSnapshot(TH32CS_SNAPPROCESS, 0)) {
+  }
+
+ private:
+  DISALLOW_EVIL_CONSTRUCTORS(ProcessEnumerator);
+};
+
+class ToolhelpModuleTraits : public ToolhelpTraits {
+ public:
+  typedef MODULEENTRY32 Type;
+
+  static bool First(HANDLE handle, Type* t) {
+    return ::Module32First(handle, t) == TRUE;
+  }
+
+  static bool Next(HANDLE handle, Type* t) {
+    return ::Module32Next(handle, t) == TRUE;
+  }
+};
+
+class ModuleEnumerator : public ToolhelpEnumeratorBase<ToolhelpModuleTraits> {
+ public:
+  explicit ModuleEnumerator(uint32 process_id)
+      : ToolhelpEnumeratorBase(
+            ToolhelpModuleTraits::CreateSnapshot(TH32CS_SNAPMODULE,
+                                                 process_id)) {
+  }
+
+ private:
+  DISALLOW_EVIL_CONSTRUCTORS(ModuleEnumerator);
+};
+
+}  // namespace rtc
+
+#endif  // WEBRTC_BASE_WIN32TOOLHELP_H_