Rename spdy_priority_tree*

net/spdy/spdy_priority_tree.h

Index: net/spdy/spdy_priority_tree.h
diff --git a/net/spdy/spdy_priority_tree.h b/net/spdy/spdy_priority_tree.h
deleted file mode 100644
index ea09c2a592b34d4134339218ecbb418bcc98bc78..0000000000000000000000000000000000000000
--- a/net/spdy/spdy_priority_tree.h
+++ /dev/null
@@ -1,563 +0,0 @@
-// Copyright 2014 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_SPDY_SPDY_PRIORITY_TREE_H_
-#define NET_SPDY_SPDY_PRIORITY_TREE_H_
-
-#include <cmath>
-#include <deque>
-#include <map>
-#include <queue>
-#include <set>
-#include <utility>
-#include <vector>
-
-#include "base/containers/hash_tables.h"
-#include "base/logging.h"
-#include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/stl_util.h"
-
-namespace net {
-
-// This data structure implements the HTTP/2 stream priority tree defined in
-// section 5.3 of RFC 7540:
-// http://tools.ietf.org/html/rfc7540#section-5.3
-//
-// Nodes can be added and removed, and dependencies between them defined.
-// Nodes constitute a tree rooted at node ID 0: each node has a single parent
-// node, and 0 or more child nodes.  Individual nodes can be marked as ready to
-// read/write, and then the whole structure can be queried to pick the next
-// node to read/write out of those that are ready.
-//
-// The NodeId type must be a POD that supports comparison (most
-// likely, it will be a number).
-
-namespace test {
-template <typename NodeId>
-class SpdyPriorityTreePeer;
-}
-
-const int kRootNodeId = 0;
-const int kDefaultWeight = 16;
-const int kMinWeight = 1;
-const int kMaxWeight = 256;
-
-template <typename NodeId>
-class SpdyPriorityTree {
- public:
-  typedef std::pair<NodeId, float> PriorityNode;
-  typedef std::vector<PriorityNode> PriorityList;
-
-  SpdyPriorityTree();
-
-  // Orders in descending order of priority.
-  struct NodePriorityComparator {
-    bool operator ()(const std::pair<NodeId, float>& lhs,
-                     const std::pair<NodeId, float>& rhs);
-  };
-
-  friend class test::SpdyPriorityTreePeer<NodeId>;
-
-  // Return the number of nodes currently in the tree.
-  int num_nodes() const;
-
-  // Return true if the tree contains a node with the given ID.
-  bool NodeExists(NodeId node_id) const;
-
-  // Add a new node with the given weight and parent. Non-exclusive nodes
-  // simply get added below the parent node. If exclusive = true, the node
-  // becomes the parent's sole child and the parent's previous children
-  // become the children of the new node.
-  // Returns true on success. Returns false if the node already exists
-  // in the tree, or if the parent node does not exist.
-  bool AddNode(NodeId node_id, NodeId parent_id, int weight, bool exclusive);
-
-  // Remove an existing node from the tree.  Returns true on success, or
-  // false if the node doesn't exist.
-  bool RemoveNode(NodeId node_id);
-
-  // Get the weight of the given node.
-  int GetWeight(NodeId node_id) const;
-
-  // Get the parent of the given node.  If the node doesn't exist, or is a root
-  // node (and thus has no parent), returns NodeId().
-  NodeId GetParent(NodeId node_id) const;
-
-  // Get the children of the given node.  If the node doesn't exist, or has no
-  // child, returns empty vector.
-  std::vector<NodeId> GetChildren(NodeId node_id) const;
-
-  // Set the priority of the given node.
-  bool SetWeight(NodeId node_id, int weight);
-
-  // Set the parent of the given node.  Returns true on success.
-  // Returns false and has no effect if the node and/or the parent doesn't
-  // exist. If the new parent is a descendant of the node (i.e. this would have
-  // created a cycle) then we rearrange the topology of the tree as described
-  // in section 5.3.3 of RFC 7540:
-  // https://tools.ietf.org/html/rfc7540#section-5.3.3
-  bool SetParent(NodeId node_id, NodeId parent_id, bool exclusive);
-
-  // Returns true if the node parent_id has child_id in its children.
-  bool HasChild(NodeId parent_id, NodeId child_id) const;
-
-  // Mark a node as blocked or unblocked. Return true on success, or false
-  // if unable to mark the specified node.
-  bool SetBlocked(NodeId node_id, bool blocked);
-
-  // Mark whether or not a node is ready to write; i.e. whether there is
-  // buffered data for the associated stream. Return true on success, or false
-  // if unable to mark the specified node.
-  bool SetReady(NodeId node_id, bool ready);
-
-  // Returns an ordered list of writeable nodes and their priorities.
-  // Priority is calculated as:
-  // parent's priority * (node's weight / sum of sibling weights)
-  PriorityList GetPriorityList();
-
- private:
-  struct Node;
-  typedef std::vector<Node*> NodeVector;
-  typedef std::map<NodeId, Node*> NodeMap;
-
-  struct Node {
-    // ID for this node.
-    NodeId id;
-    // ID of parent node.
-    Node* parent = nullptr;
-    // Weights can range between 1 and 256 (inclusive).
-    int weight = kDefaultWeight;
-    // The total weight of this node's direct descendants.
-    int total_child_weights = 0;
-    // The total weight of direct descendants that are writeable
-    // (ready to write and not blocked). This value does not necessarily
-    // reflect the current state of the tree; instead, we lazily update it
-    // on calls to PropagateNodeState().
-    int total_writeable_child_weights = 0;
-    // Pointers to nodes for children, if any.
-    NodeVector children;
-    // Is the associated stream write-blocked?
-    bool blocked = false;
-    // Does the stream have data ready for writing?
-    bool ready = false;
-    // The fraction of resources to dedicate to this node.
-    float priority = 0;
-  };
-
-  static bool Remove(NodeVector* nodes, const Node* node);
-
-  // Update the value of total_writeable_child_weights for the given node
-  // to reflect the current state of the tree.
-  void PropagateNodeState(Node* node);
-
-  // Get the given node, or return nullptr if it doesn't exist.
-  const Node* FindNode(NodeId node_id) const;
-  Node* FindNode(NodeId node_id);
-
-  // Return true if all internal invariants hold (useful for unit tests).
-  // Unless there are bugs, this should always return true.
-  bool ValidateInvariantsForTests() const;
-
-  Node* root_node_;    // pointee owned by all_nodes_
-  NodeMap all_nodes_;  // maps from node IDs to Node objects
-  STLValueDeleter<NodeMap> all_nodes_deleter_;
-
-  DISALLOW_COPY_AND_ASSIGN(SpdyPriorityTree);
-};
-
-template <typename NodeId>
-SpdyPriorityTree<NodeId>::SpdyPriorityTree()
-    : all_nodes_deleter_(&all_nodes_) {
-  root_node_ = new Node();
-  root_node_->id = kRootNodeId;
-  root_node_->weight = kDefaultWeight;
-  root_node_->parent = nullptr;
-  root_node_->priority = 1.0;
-  root_node_->ready = true;
-  all_nodes_[kRootNodeId] = root_node_;
-}
-
-template <typename NodeId>
-bool SpdyPriorityTree<NodeId>::NodePriorityComparator::operator()(
-    const std::pair<NodeId, float>& lhs,
-    const std::pair<NodeId, float>& rhs) {
-  return lhs.second > rhs.second;
-}
-
-template <typename NodeId>
-int SpdyPriorityTree<NodeId>::num_nodes() const {
-  return all_nodes_.size();
-}
-
-template <typename NodeId>
-bool SpdyPriorityTree<NodeId>::NodeExists(NodeId node_id) const {
-  return ContainsKey(all_nodes_, node_id);
-}
-
-template <typename NodeId>
-bool SpdyPriorityTree<NodeId>::AddNode(NodeId node_id,
-                                       NodeId parent_id,
-                                       int weight,
-                                       bool exclusive) {
-  if (NodeExists(node_id) || weight < kMinWeight || weight > kMaxWeight) {
-    return false;
-  }
-  Node* parent = FindNode(parent_id);
-  if (parent == nullptr) {
-    return false;
-  }
-  Node* new_node = new Node;
-  new_node->id = node_id;
-  new_node->weight = weight;
-  new_node->parent = parent;
-  all_nodes_[node_id] = new_node;
-  if (exclusive) {
-    // Move the parent's current children below the new node.
-    using std::swap;
-    swap(new_node->children, parent->children);
-    new_node->total_child_weights = parent->total_child_weights;
-    // Update each child's parent.
-    for (Node* child : new_node->children) {
-      child->parent = new_node;
-    }
-    // Clear parent's old child data.
-    DCHECK(parent->children.empty());
-    parent->total_child_weights = 0;
-  }
-  // Add new node to parent.
-  parent->children.push_back(new_node);
-  parent->total_child_weights += weight;
-  return true;
-}
-
-template <typename NodeId>
-bool SpdyPriorityTree<NodeId>::RemoveNode(NodeId node_id) {
-  if (node_id == kRootNodeId) {
-    return false;
-  }
-  // Remove the node from table.
-  typename NodeMap::iterator it = all_nodes_.find(node_id);
-  if (it == all_nodes_.end()) {
-    return false;
-  }
-  scoped_ptr<Node> node(it->second);
-  all_nodes_.erase(it);
-
-  Node* parent = node->parent;
-  // Remove the node from parent's child list.
-  Remove(&parent->children, node.get());
-  parent->total_child_weights -= node->weight;
-
-  // Move the node's children to the parent's child list.
-  // Update each child's parent and weight.
-  for (Node* child : node->children) {
-    child->parent = parent;
-    parent->children.push_back(child);
-    // Divide the removed node's weight among its children, rounding to the
-    // nearest valid weight.
-    float float_weight = node->weight * static_cast<float>(child->weight) /
-                         static_cast<float>(node->total_child_weights);
-    int new_weight = floor(float_weight + 0.5);
-    if (new_weight == 0) {
-      new_weight = 1;
-    }
-    child->weight = new_weight;
-    parent->total_child_weights += child->weight;
-  }
-
-  return true;
-}
-
-template <typename NodeId>
-int SpdyPriorityTree<NodeId>::GetWeight(NodeId node_id) const {
-  const Node* node = FindNode(node_id);
-  return (node == nullptr) ? 0 : node->weight;
-}
-
-template <typename NodeId>
-NodeId SpdyPriorityTree<NodeId>::GetParent(NodeId node_id) const {
-  const Node* node = FindNode(node_id);
-  // Root node has null parent.
-  return (node == nullptr || node->parent == nullptr) ? kRootNodeId
-                                                      : node->parent->id;
-}
-
-template <typename NodeId>
-std::vector<NodeId> SpdyPriorityTree<NodeId>::GetChildren(
-    NodeId node_id) const {
-  std::vector<NodeId> child_vec;
-  const Node* node = FindNode(node_id);
-  if (node != nullptr) {
-    child_vec.reserve(node->children.size());
-    for (Node* child : node->children) {
-      child_vec.push_back(child->id);
-    }
-  }
-  return child_vec;
-}
-
-template <typename NodeId>
-bool SpdyPriorityTree<NodeId>::SetWeight(
-    NodeId node_id, int weight) {
-  if (!NodeExists(node_id)) {
-    return false;
-  }
-  if (weight < kMinWeight || weight > kMaxWeight) {
-    return false;
-  }
-
-  Node* node = all_nodes_[node_id];
-  if (node->parent != nullptr) {
-    node->parent->total_child_weights += (weight - node->weight);
-  }
-  node->weight = weight;
-
-  return true;
-}
-
-
-template <typename NodeId>
-bool SpdyPriorityTree<NodeId>::SetParent(
-    NodeId node_id, NodeId parent_id, bool exclusive) {
-  if (node_id == kRootNodeId || node_id == parent_id) {
-    return false;
-  }
-  Node* node = FindNode(node_id);
-  Node* new_parent = FindNode(parent_id);
-  if (node == nullptr || new_parent == nullptr) {
-    return false;
-  }
-
-  // If the new parent is already the node's parent, we're done.
-  if (node->parent == new_parent) {
-    return true;
-  }
-
-  // Next, check to see if the new parent is currently a descendant
-  // of the node.
-  Node* last = new_parent->parent;
-  bool cycle_exists = false;
-  while (last != nullptr) {
-    if (last == node) {
-      cycle_exists = true;
-      break;
-    }
-    last = last->parent;
-  }
-
-  if (cycle_exists) {
-    // The new parent moves to the level of the current node.
-    SetParent(parent_id, node->parent->id, false);
-  }
-
-  // Remove node from old parent's child list.
-  Node* old_parent = node->parent;
-  Remove(&old_parent->children, node);
-  old_parent->total_child_weights -= node->weight;
-
-  if (exclusive) {
-    // Move the new parent's current children below the current node.
-    for (Node* child : new_parent->children) {
-      child->parent = node;
-      node->children.push_back(child);
-    }
-    node->total_child_weights += new_parent->total_child_weights;
-    // Clear new parent's old child data.
-    new_parent->children.clear();
-    new_parent->total_child_weights = 0;
-  }
-
-  // Make the change.
-  node->parent = new_parent;
-  new_parent->children.push_back(node);
-  new_parent->total_child_weights += node->weight;
-  return true;
-}
-
-template <typename NodeId>
-bool SpdyPriorityTree<NodeId>::SetBlocked(NodeId node_id, bool blocked) {
-  if (!NodeExists(node_id)) {
-    return false;
-  }
-
-  Node* node = all_nodes_[node_id];
-  node->blocked = blocked;
-  return true;
-}
-
-template <typename NodeId>
-bool SpdyPriorityTree<NodeId>::SetReady(NodeId node_id, bool ready) {
-  if (!NodeExists(node_id)) {
-    return false;
-  }
-  Node* node = all_nodes_[node_id];
-  node->ready = ready;
-  return true;
-}
-
-template <typename NodeId>
-bool SpdyPriorityTree<NodeId>::Remove(NodeVector* nodes, const Node* node) {
-  for (typename NodeVector::iterator it = nodes->begin(); it != nodes->end();
-       ++it) {
-    if (*it == node) {
-      nodes->erase(it);
-      return true;
-    }
-  }
-  return false;
-}
-
-template <typename NodeId>
-void SpdyPriorityTree<NodeId>::PropagateNodeState(Node* node) {
-  // Reset total_writeable_child_weights to its maximum value.
-  node->total_writeable_child_weights = node->total_child_weights;
-  for (Node* child : node->children) {
-    PropagateNodeState(child);
-  }
-  if (node->total_writeable_child_weights == 0 &&
-      (node->blocked || !node->ready)) {
-    // Tell the parent that this entire subtree is unwriteable.
-    node->parent->total_writeable_child_weights -= node->weight;
-  }
-}
-
-template <typename NodeId>
-const typename SpdyPriorityTree<NodeId>::Node*
-SpdyPriorityTree<NodeId>::FindNode(NodeId node_id) const {
-  typename NodeMap::const_iterator it = all_nodes_.find(node_id);
-  return (it == all_nodes_.end() ? nullptr : it->second);
-}
-
-template <typename NodeId>
-typename SpdyPriorityTree<NodeId>::Node* SpdyPriorityTree<NodeId>::FindNode(
-    NodeId node_id) {
-  typename NodeMap::const_iterator it = all_nodes_.find(node_id);
-  return (it == all_nodes_.end() ? nullptr : it->second);
-}
-
-template <typename NodeId>
-bool SpdyPriorityTree<NodeId>::HasChild(NodeId parent_id,
-                                        NodeId child_id) const {
-  const Node* parent = FindNode(parent_id);
-  if (parent == nullptr) {
-    return false;
-  }
-  auto found =
-      std::find_if(parent->children.begin(), parent->children.end(),
-                   [child_id](Node* node) { return node->id == child_id; });
-  return found != parent->children.end();
-}
-
-template <typename NodeId>
-std::vector<std::pair<NodeId, float> >
-SpdyPriorityTree<NodeId>::GetPriorityList() {
-  PriorityList priority_list;
-
-  // Update total_writeable_child_weights to reflect the current
-  // state of the tree.
-  PropagateNodeState(root_node_);
-
-  std::deque<Node*> queue;
-  DCHECK(root_node_->priority == 1.0);
-  // Start by examining our top-level nodes.
-  for (Node* child : root_node_->children) {
-    queue.push_back(child);
-  }
-  while (!queue.empty()) {
-    Node* current_node = queue.front();
-    const Node* parent_node = current_node->parent;
-    if (current_node->blocked || !current_node->ready) {
-      if (current_node->total_writeable_child_weights > 0) {
-        // This node isn't writeable, but it has writeable children.
-        // Calculate the total fraction of resources we can allot
-        // to this subtree.
-        current_node->priority = parent_node->priority *
-            (static_cast<float>(current_node->weight) /
-             static_cast<float>(parent_node->total_writeable_child_weights));
-        // Examine the children.
-        for (Node* child : current_node->children) {
-          queue.push_back(child);
-        }
-      } else {
-        // There's nothing to see in this subtree.
-        current_node->priority = 0;
-      }
-    } else {
-      // This node is writeable; calculate its priority.
-      current_node->priority = parent_node->priority *
-          (static_cast<float>(current_node->weight) /
-           static_cast<float>(parent_node->total_writeable_child_weights));
-      // Add this node to the priority list.
-      priority_list.push_back(
-          PriorityNode(current_node->id, current_node->priority));
-    }
-    // Remove this node from the queue.
-    queue.pop_front();
-  }
-
-  // Sort the nodes in descending order of priority.
-  std::sort(priority_list.begin(), priority_list.end(),
-            NodePriorityComparator());
-
-  return priority_list;
-}
-
-template <typename NodeId>
-bool SpdyPriorityTree<NodeId>::ValidateInvariantsForTests() const {
-  int total_nodes = 0;
-  int nodes_visited = 0;
-  // Iterate through all nodes in the map.
-  for (const auto& kv : all_nodes_) {
-    ++total_nodes;
-    ++nodes_visited;
-    const Node& node = *kv.second;
-    // All nodes except the root should have a parent, and should appear in
-    // the children of that parent.
-    if (node.id != kRootNodeId && !HasChild(node.parent->id, node.id)) {
-      DLOG(INFO) << "Parent node " << node.parent->id
-                 << " does not exist, or does not list node " << node.id
-                 << " as its child.";
-      return false;
-    }
-
-    if (!node.children.empty()) {
-      int total_child_weights = 0;
-      // Iterate through the node's children.
-      for (Node* child : node.children) {
-        ++nodes_visited;
-        // Each node in the list should exist and should have this node
-        // set as its parent.
-        if (!NodeExists(child->id) || node.id != GetParent(child->id)) {
-          DLOG(INFO) << "Child node " << child->id << " does not exist, "
-                     << "or does not list " << node.id << " as its parent.";
-          return false;
-        }
-        total_child_weights += child->weight;
-      }
-      // Verify that total_child_weights is correct.
-      if (total_child_weights != node.total_child_weights) {
-        DLOG(INFO) << "Child weight totals do not agree. For node " << node.id
-                   << " total_child_weights has value "
-                   << node.total_child_weights
-                   << ", expected " << total_child_weights;
-        return false;
-      }
-    }
-  }
-
-  // Make sure num_nodes reflects the total number of nodes the map contains.
-  if (total_nodes != num_nodes()) {
-    DLOG(INFO) << "Map contains incorrect number of nodes.";
-    return false;
-  }
-  // Validate the validation function; we should have visited each node twice
-  // (except for the root)
-  DCHECK(nodes_visited == 2*num_nodes() - 1);
-  return true;
-}
-
-}  // namespace net
-
-#endif  // NET_SPDY_SPDY_PRIORITY_TREE_H_