Initial source checkin.

The source files were determined by building net_unittests in chromium's source
tree. Some of the obvious libraries were left out (v8, gmock, gtest).

The Android.mk file has all the sources (minus unittests and tools) that were
used during net_unittests compilation. Nothing builds yet because of STL but
that is the next task. The .cpp files will most likely not compile anyways
because of the LOCAL_CPP_EXTENSION mod. I will have to break this into multiple
projects to get around that limitation.

1 files changed, 164 insertions, 0 deletions

diff --git a/base/linked_list.h b/base/linked_list.h
new file mode 100644
index 0000000..5b5184f
--- /dev/null
+++ b/base/linked_list.h
@@ -0,0 +1,164 @@
+// 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_LINKED_LIST_H_
+#define BASE_LINKED_LIST_H_
+
+// Simple LinkedList type. (See the Q&A section to understand how this
+// differs from std::list).
+//
+// To use, start by declaring the class which will be contained in the linked
+// list, as extending LinkNode (this gives it next/previous pointers).
+//
+//   class MyNodeType : public LinkNode<MyNodeType> {
+//     ...
+//   };
+//
+// Next, to keep track of the list's head/tail, use a LinkedList instance:
+//
+//   LinkedList<MyNodeType> list;
+//
+// To add elements to the list, use any of LinkedList::Append,
+// LinkNode::InsertBefore, or LinkNode::InsertAfter:
+//
+//   LinkNode<MyNodeType>* n1 = ...;
+//   LinkNode<MyNodeType>* n2 = ...;
+//   LinkNode<MyNodeType>* n3 = ...;
+//
+//   list.Append(n1);
+//   list.Append(n3);
+//   n3->InsertBefore(n3);
+//
+// Lastly, to iterate through the linked list forwards:
+//
+//   for (LinkNode<MyNodeType>* node = list.head();
+//        node != list.end();
+//        node = node->next()) {
+//     MyNodeType* value = node->value();
+//     ...
+//   }
+//
+// Or to iterate the linked list backwards:
+//
+//   for (LinkNode<MyNodeType>* node = list.tail();
+//        node != list.end();
+//        node = node->previous()) {
+//     MyNodeType* value = node->value();
+//     ...
+//   }
+//
+// Questions and Answers:
+//
+// Q. Should I use std::list or base::LinkedList?
+//
+// A. The main reason to use base::LinkedList over std::list is
+//    performance. If you don't care about the performance differences
+//    then use an STL container, as it makes for better code readability.
+//
+//    Comparing the performance of base::LinkedList<T> to std::list<T*>:
+//
+//    * Erasing an element of type T* from base::LinkedList<T> is
+//      an O(1) operation. Whereas for std::list<T*> it is O(n).
+//      That is because with std::list<T*> you must obtain an
+//      iterator to the T* element before you can call erase(iterator).
+//
+//    * Insertion operations with base::LinkedList<T> never require
+//      heap allocations.
+//
+// Q. How does base::LinkedList implementation differ from std::list?
+//
+// A. Doubly-linked lists are made up of nodes that contain "next" and
+//    "previous" pointers that reference other nodes in the list.
+//
+//    With base::LinkedList<T>, the type being inserted already reserves
+//    space for the "next" and "previous" pointers (base::LinkNode<T>*).
+//    Whereas with std::list<T> the type can be anything, so the implementation
+//    needs to glue on the "next" and "previous" pointers using
+//    some internal node type.
+
+namespace base {
+
+template <typename T>
+class LinkNode {
+ public:
+  LinkNode() : previous_(0), next_(0) {}
+  LinkNode(LinkNode<T>* previous, LinkNode<T>* next)
+      : previous_(previous), next_(next) {}
+
+  // Insert |this| into the linked list, before |e|.
+  void InsertBefore(LinkNode<T>* e) {
+    this->next_ = e;
+    this->previous_ = e->previous_;
+    e->previous_->next_ = this;
+    e->previous_ = this;
+  }
+
+  // Insert |this| into the linked list, after |e|.
+  void InsertAfter(LinkNode<T>* e) {
+    this->next_ = e->next_;
+    this->previous_ = e;
+    e->next_->previous_ = this;
+    e->next_ = this;
+  }
+
+  // Remove |this| from the linked list.
+  void RemoveFromList() {
+    this->previous_->next_ = this->next_;
+    this->next_->previous_ = this->previous_;
+  }
+
+  LinkNode<T>* previous() const {
+    return previous_;
+  }
+
+  LinkNode<T>* next() const {
+    return next_;
+  }
+
+  // Cast from the node-type to the value type.
+  const T* value() const {
+    return static_cast<const T*>(this);
+  }
+
+  T* value() {
+    return static_cast<T*>(this);
+  }
+
+ private:
+  LinkNode<T>* previous_;
+  LinkNode<T>* next_;
+};
+
+template <typename T>
+class LinkedList {
+ public:
+  // The "root" node is self-referential, and forms the basis of a circular
+  // list (root_.next() will point back to the start of the list,
+  // and root_->previous() wraps around to the end of the list).
+  LinkedList() : root_(&root_, &root_) {}
+
+  // Appends |e| to the end of the linked list.
+  void Append(LinkNode<T>* e) {
+    e->InsertBefore(&root_);
+  }
+
+  LinkNode<T>* head() const {
+    return root_.next();
+  }
+
+  LinkNode<T>* tail() const {
+    return root_.previous();
+  }
+
+  const LinkNode<T>* end() const {
+    return &root_;
+  }
+
+ private:
+  LinkNode<T> root_;
+};
+
+}  // namespace base
+
+#endif  // BASE_LINKED_LIST_H_