Move debug-related stuff from base to the base/debug directory and use the...

base/leak_tracker.h

-// Copyright (c) 2009 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 BASE_LEAK_TRACKER_H_
-#define BASE_LEAK_TRACKER_H_
-#pragma once
-
-// Only enable leak tracking in debug builds.
-#ifndef NDEBUG
-#define ENABLE_LEAK_TRACKER
-#endif
-
-#ifdef ENABLE_LEAK_TRACKER
-#include "base/debug_util.h"
-#include "base/linked_list.h"
-#include "base/logging.h"
-#endif  // ENABLE_LEAK_TRACKER
-
-// LeakTracker is a helper to verify that all instances of a class
-// have been destroyed.
-//
-// It is particularly useful for classes that are bound to a single thread --
-// before destroying that thread, one can check that there are no remaining
-// instances of that class.
-//
-// For example, to enable leak tracking for class URLRequest, start by
-// adding a member variable of type LeakTracker<URLRequest>.
-//
-//   class URLRequest {
-//     ...
-//    private:
-//     base::LeakTracker<URLRequest> leak_tracker_;
-//   };
-//
-//
-// Next, when we believe all instances of URLRequest have been deleted:
-//
-//   LeakTracker<URLRequest>::CheckForLeaks();
-//
-// Should the check fail (because there are live instances of URLRequest),
-// then the allocation callstack for each leaked instances is dumped to
-// the error log.
-//
-// If ENABLE_LEAK_TRACKER is not defined, then the check has no effect.
-
-namespace base {
-
-#ifndef ENABLE_LEAK_TRACKER
-
-// If leak tracking is disabled, do nothing.
-template<typename T>
-class LeakTracker {
- public:
-  static void CheckForLeaks() {}
-  static int NumLiveInstances() { return -1; }
-};
-
-#else
-
-// If leak tracking is enabled we track where the object was allocated from.
-
-template<typename T>
-class LeakTracker : public LinkNode<LeakTracker<T> > {
- public:
-  LeakTracker() {
-    instances()->Append(this);
-  }
-
-  ~LeakTracker() {
-    this->RemoveFromList();
-  }
-
-  static void CheckForLeaks() {
-    // Walk the allocation list and print each entry it contains.
-    size_t count = 0;
-
-    // Copy the first 3 leak allocation callstacks onto the stack.
-    // This way if we hit the CHECK() in a release build, the leak
-    // information will be available in mini-dump.
-    const size_t kMaxStackTracesToCopyOntoStack = 3;
-    StackTrace stacktraces[kMaxStackTracesToCopyOntoStack];
-
-    for (LinkNode<LeakTracker<T> >* node = instances()->head();
-         node != instances()->end();
-         node = node->next()) {
-      StackTrace& allocation_stack = node->value()->allocation_stack_;
-
-      if (count < kMaxStackTracesToCopyOntoStack)
-        stacktraces[count] = allocation_stack;
-
-      ++count;
-      LOG(ERROR) << "Leaked " << node << " which was allocated by:";
-      allocation_stack.OutputToStream(&LOG_STREAM(ERROR));
-    }
-
-    CHECK_EQ(0u, count);
-
-    // Hack to keep |stacktraces| and |count| alive (so compiler
-    // doesn't optimize it out, and it will appear in mini-dumps).
-    if (count == 0x1234) {
-      for (size_t i = 0; i < kMaxStackTracesToCopyOntoStack; ++i)
-        stacktraces[i].PrintBacktrace();
-    }
-  }
-
-  static int NumLiveInstances() {
-    // Walk the allocation list and count how many entries it has.
-    int count = 0;
-    for (LinkNode<LeakTracker<T> >* node = instances()->head();
-         node != instances()->end();
-         node = node->next()) {
-      ++count;
-    }
-    return count;
-  }
-
- private:
-  // Each specialization of LeakTracker gets its own static storage.
-  static LinkedList<LeakTracker<T> >* instances() {
-    static LinkedList<LeakTracker<T> > list;
-    return &list;
-  }
-
-  StackTrace allocation_stack_;
-};
-
-#endif  // ENABLE_LEAK_TRACKER
-
-}  // namespace base
-
-#endif  // BASE_LEAK_TRACKER_H_