MJPEG acceleration for video capture using VAAPI

base/containers/scoped_ptr_hash_map.h

 // Copyright 2013 The Chromium Authors. All rights reserved.

[kcwu, 2015/04/23 13:02:32]

change of scoped_ptr_hash_map* is under review here
https://codereview.chromium.org/1099383002/

 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_CONTAINERS_SCOPED_PTR_HASH_MAP_H_
 #define BASE_CONTAINERS_SCOPED_PTR_HASH_MAP_H_
 
 #include <algorithm>
 #include <utility>
 
 #include "base/basictypes.h"
 #include "base/containers/hash_tables.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/stl_util.h"
 
 namespace base {
 
-// This type acts like a hash_map<K, scoped_ptr<V> >, based on top of
+// This type acts like a hash_map<K, scoped_ptr<V, D> >, based on top of
 // base::hash_map. The ScopedPtrHashMap has ownership of all values in the data
 // structure.
-template <typename Key, typename Value>
+template <typename Key,
+          typename Value,
+          typename Deleter = base::DefaultDeleter<Value>>
 class ScopedPtrHashMap {
   typedef base::hash_map<Key, Value*> Container;
 
  public:
   typedef typename Container::key_type key_type;
   typedef typename Container::mapped_type mapped_type;
   typedef typename Container::value_type value_type;
   typedef typename Container::iterator iterator;
   typedef typename Container::const_iterator const_iterator;
 
   ScopedPtrHashMap() {}
 
   ~ScopedPtrHashMap() { clear(); }
 
-  void swap(ScopedPtrHashMap<Key, Value>& other) {
+  void swap(ScopedPtrHashMap<Key, Value, Deleter>& other) {
     data_.swap(other.data_);
   }
 
   // Replaces value but not key if key is already present.
-  iterator set(const Key& key, scoped_ptr<Value> data) {
+  iterator set(const Key& key, scoped_ptr<Value, Deleter> data) {
     iterator it = find(key);
     if (it != end()) {
-      delete it->second;
+      Deleter()(it->second);
       it->second = data.release();
       return it;
     }
 
     return data_.insert(std::make_pair(key, data.release())).first;
   }
 
   // Does nothing if key is already present
-  std::pair<iterator, bool> add(const Key& key, scoped_ptr<Value> data) {
+  std::pair<iterator, bool> add(const Key& key,
+                                scoped_ptr<Value, Deleter> data) {
     std::pair<iterator, bool> result =
         data_.insert(std::make_pair(key, data.get()));
     if (result.second)
       ignore_result(data.release());
     return result;
   }
 
   void erase(iterator it) {
-    delete it->second;
+    Deleter()(it->second);
     data_.erase(it);
   }
 
   size_t erase(const Key& k) {
     iterator it = data_.find(k);
     if (it == data_.end())
       return 0;
     erase(it);
     return 1;
   }
 
-  scoped_ptr<Value> take(iterator it) {
+  scoped_ptr<Value, Deleter> take(iterator it) {
     DCHECK(it != data_.end());
     if (it == data_.end())
-      return scoped_ptr<Value>();
+      return scoped_ptr<Value, Deleter>();
 
-    scoped_ptr<Value> ret(it->second);
+    scoped_ptr<Value, Deleter> ret(it->second);
     it->second = NULL;
     return ret.Pass();
   }
 
-  scoped_ptr<Value> take(const Key& k) {
+  scoped_ptr<Value, Deleter> take(const Key& k) {
     iterator it = find(k);
     if (it == data_.end())
-      return scoped_ptr<Value>();
+      return scoped_ptr<Value, Deleter>();
 
     return take(it);
   }
 
-  scoped_ptr<Value> take_and_erase(iterator it) {
+  scoped_ptr<Value, Deleter> take_and_erase(iterator it) {
     DCHECK(it != data_.end());
     if (it == data_.end())
-      return scoped_ptr<Value>();
+      return scoped_ptr<Value, Deleter>();
 
-    scoped_ptr<Value> ret(it->second);
+    scoped_ptr<Value, Deleter> ret(it->second);
     data_.erase(it);
     return ret.Pass();
   }
 
-  scoped_ptr<Value> take_and_erase(const Key& k) {
+  scoped_ptr<Value, Deleter> take_and_erase(const Key& k) {
     iterator it = find(k);
     if (it == data_.end())
-      return scoped_ptr<Value>();
+      return scoped_ptr<Value, Deleter>();
 
     return take_and_erase(it);
   }
 
   // Returns the element in the hash_map that matches the given key.
   // If no such element exists it returns NULL.
   Value* get(const Key& k) const {
     const_iterator it = find(k);
     if (it == end())
       return NULL;
     return it->second;
   }
 
   inline bool contains(const Key& k) const { return data_.count(k) > 0; }
 
-  inline void clear() { STLDeleteValues(&data_); }
+  inline void clear() {
+    auto it = data_.begin();
+    while (it != data_.end()) {
+      // NOTE: Like STLDeleteContainerPointers, deleting behind the iterator.
+      // Deleting the value does not always invalidate the iterator, but it may
+      // do so if the key is a pointer into the value object.
+      auto temp = it;
+      ++it;
+      Deleter()(temp->second);
+    }
+    data_.clear();
+  }
 
   inline const_iterator find(const Key& k) const { return data_.find(k); }
   inline iterator find(const Key& k) { return data_.find(k); }
 
   inline size_t count(const Key& k) const { return data_.count(k); }
   inline std::pair<const_iterator, const_iterator> equal_range(
       const Key& k) const {
     return data_.equal_range(k);
   }
   inline std::pair<iterator, iterator> equal_range(const Key& k) {
@@ skipping 15 matching lines @@
 
  private:
   Container data_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedPtrHashMap);
 };
 
 }  // namespace base
 
 #endif  // BASE_CONTAINERS_SCOPED_PTR_HASH_MAP_H_