Remove service-compiler related code.

pkg/servicec/lib/cycle_detection.dart

-// Copyright (c) 2015, the Dartino project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-library servicec.cycle_detection;
-
-import 'dart:collection' show
-    LinkedHashSet;
-
-import 'node.dart' show
-    MemberNode,
-    FieldNode,
-    SimpleType,
-    StructNode,
-    TypeNode,
-    UnionNode;
-
-import 'errors.dart' show
-    CompilationError,
-    CyclicStructError,
-    ErrorTag;
-
-class GraphNode {
-  GraphNodeState state = GraphNodeState.UNVISITED;
-  StructNode struct;
-
-  GraphNode(this.struct);
-
-  bool get isNotVisited => GraphNodeState.UNVISITED == state;
-
-  bool operator ==(GraphNode other) {
-    return struct == other.struct;
-  }
-  int get hashCode => struct.hashCode;
-
-  String toString() => "Node[${struct.identifier.value}, ${state.toString()}]";
-}
-
-enum GraphNodeState {
-  VISITED,
-  VISITING,
-  UNVISITED
-}
-
-class StructGraph {
-  Set<GraphNode> nodes;
-  Map<GraphNode, Set<GraphNode>> neighbours;
-
-  StructGraph()
-    : nodes = new LinkedHashSet<GraphNode>(),  // Maintain node order.
-      neighbours = new Map<GraphNode, Set<GraphNode>>();
-
-  void add(StructNode struct) {
-    for (MemberNode member in struct.members) {
-      if (member is FieldNode) {
-        addStructField(struct, member);
-      } else {
-        UnionNode union = member;
-        union.fields.forEach((field) => addStructField(struct, field));
-      }
-    }
-  }
-
-  // Helper function.
-  void addStructField(StructNode struct, FieldNode field) {
-    TypeNode type = field.type;
-    if (type != null && type.isStruct()) {
-      SimpleType simpleType = type;
-      addLink(struct, simpleType.resolved);
-    }
-  }
-
-  void addLink(StructNode from, StructNode to) {
-    GraphNode fromNode = addNodeIfNew(from);
-    GraphNode toNode = addNodeIfNew(to);
-    neighbours[fromNode].add(toNode);
-  }
-
-  GraphNode addNodeIfNew(StructNode node) {
-    GraphNode result = nodes.firstWhere(
-        (graphNode) => graphNode.struct == node,
-        orElse: () => null);
-    if (null == result) {
-      result = new GraphNode(node);
-      nodes.add(result);
-      neighbours[result] = new Set<GraphNode>();
-    }
-    return result;
-  }
-
-  List<CompilationError> findCycles() {
-    List<CompilationError> errors = <CompilationError>[];
-    List<GraphNode> stack = new List<GraphNode>();
-    stack.addAll(nodes.toList().reversed.toList());
-    while (stack.isNotEmpty) {
-      GraphNode node = stack.last;
-      switch (node.state) {
-        case GraphNodeState.UNVISITED:
-          node.state = GraphNodeState.VISITING;
-          for (GraphNode neighbour in neighbours[node]) {
-            switch (neighbour.state) {
-              case GraphNodeState.UNVISITED:
-                // The `neighbour` hasn't been seen yet - add to stack.
-                stack.add(neighbour);
-                break;
-              case GraphNodeState.VISITING:
-                // The `neighbour` is in the current route from the root to the
-                // `node` - there is a cycle.
-                errors.add(createError(neighbour.struct, stack));
-                break;
-              case GraphNodeState.VISITED:
-                // The `neighbour` has already been searched - ignore.
-                break;
-            }
-          }
-          break;
-        case GraphNodeState.VISITING:
-          node.state = GraphNodeState.VISITED;
-          stack.removeLast();
-          break;
-        case GraphNodeState.VISITED:
-          // In this case the graph is a DAG.
-          stack.removeLast();
-          break;
-      }
-    }
-    return errors;
-  }
-
-  CyclicStructError createError(StructNode struct, List<GraphNode> stack) {
-    LinkedHashSet<StructNode> reversedChain = new LinkedHashSet<StructNode>();
-    reversedChain.add(struct);
-    for (int i = stack.length - 1; i >= 0; --i) {
-      if (stack[i].state == GraphNodeState.VISITING) {
-        reversedChain.add(stack[i].struct);
-      }
-      if (stack[i].struct == struct) break;
-    }
-
-    return new CyclicStructError(reversedChain.toList().reversed);
-  }
-}