Compete try-statements

pkg/analysis_server/lib/src/services/completion/statement/statement_completion.dart

 // Copyright (c) 2017, the Dart 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 services.src.completion.statement;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
@@ skipping 25 matching lines @@
   static const COMPLETE_DO_STMT = const StatementCompletionKind(
       'COMPLETE_DO_STMT', "Complete do-statement");
   static const COMPLETE_IF_STMT = const StatementCompletionKind(
       'COMPLETE_IF_STMT', "Complete if-statement");
   static const COMPLETE_FOR_STMT = const StatementCompletionKind(
       'COMPLETE_FOR_STMT', "Complete for-statement");
   static const COMPLETE_FOR_EACH_STMT = const StatementCompletionKind(
       'COMPLETE_FOR_EACH_STMT', "Complete for-each-statement");
   static const COMPLETE_SWITCH_STMT = const StatementCompletionKind(
       'COMPLETE_SWITCH_STMT', "Complete switch-statement");
+  static const COMPLETE_TRY_STMT = const StatementCompletionKind(
+      'COMPLETE_TRY_STMT', "Complete try-statement");
   static const COMPLETE_WHILE_STMT = const StatementCompletionKind(
       'COMPLETE_WHILE_STMT', "Complete while-statement");
 }
 
 /**
  * A description of a statement completion.
  *
  * Clients may not extend, implement or mix-in this class.
  */
 class StatementCompletion {
@@ skipping 128 matching lines @@
 
     // TODO(messick) Consider changing (some of) this to a visitor.
     if (_complete_ifStatement() ||
         _complete_doStatement() ||
         _complete_forStatement() ||
         _complete_forEachStatement() ||
         _complete_switchStatement() ||
         _complete_tryStatement() ||
         _complete_whileStatement() ||
         _complete_simpleSemicolon() ||
+        _complete_controlFlowBlock() ||
         _complete_simpleEnter()) {
       return completion;
     }
     return NO_COMPLETION;
   }
 
   void _addInsertEdit(int offset, String text) {
     SourceEdit edit = new SourceEdit(offset, 0, text);
     doSourceChange_addElementEdit(change, unitElement, edit);
   }
@@ skipping 80 matching lines @@
     }
     SourceBuilder sb2;
     if (hasWhileKeyword) {
       var stmt = new _KeywordConditionBlockStructure(
           statement.whileKeyword,
           statement.leftParenthesis,
           statement.condition,
           statement.rightParenthesis,
           null);
       sb2 = _complete_keywordCondition(stmt);
+      if (sb2 == null) {
+        return false;
+      }
       if (sb2.length == 0) {
         // true if condition is '()'
         if (exitPosition != null) {
           if (statement.semicolon.isSynthetic) {
             _insertBuilder(sb);
             sb = new SourceBuilder(file, exitPosition.offset + 1);
             sb.append(';');
           }
         }
       } else {
@@ skipping 143 matching lines @@
       exitPosition = new Position(file, exitPosition.offset - delta);
     }
     _insertBuilder(sb);
     _setCompletion(DartStatementCompletion.COMPLETE_FOR_STMT);
     return true;
   }
 
   bool _complete_ifOrWhileStatement(
       _KeywordConditionBlockStructure statement, StatementCompletionKind kind) {
     SourceBuilder sb = _complete_keywordCondition(statement);
+    if (sb == null) {
+      return false;
+    }
     if (statement.block is EmptyStatement) {
       sb.append(' ');
       _appendEmptyBraces(sb, exitPosition == null);
     }
     _insertBuilder(sb);
     _setCompletion(kind);
     return true;
   }
 
   bool _complete_ifStatement() {
@@ skipping 103 matching lines @@
       // See https://github.com/dart-lang/sdk/issues/29391
       sb.append(' ');
       _appendEmptyBraces(sb, exitPosition == null);
     }
     _insertBuilder(sb);
     _setCompletion(DartStatementCompletion.COMPLETE_SWITCH_STMT);
     return true;
   }
 
   bool _complete_tryStatement() {
-    // TODO(messick) Implement _complete_tryStatement
-    return false;
+    if (errors.isEmpty || node is! TryStatement) {
+      return false;
+    }
+    TryStatement tryNode = node;
+    SourceBuilder sb;
+    CatchClause catchNode;
+    bool addSpace = true;
+    if (tryNode.body.leftBracket.isSynthetic) {
+      String src = utils.getNodeText(tryNode);
+      if (src
+          .substring(tryNode.tryKeyword.end - tryNode.offset)
+          .startsWith(new RegExp(r'[ \t]+'))) {
+        // keywordSpace
+        sb = new SourceBuilder(file, tryNode.tryKeyword.end + 1);
+      } else {
+        // keywordOnly
+        sb = new SourceBuilder(file, tryNode.tryKeyword.end);
+        sb.append(' ');
+      }
+      _appendEmptyBraces(sb, true);
+      _insertBuilder(sb);
+      sb = null;
+    } else if ((catchNode = _firstInvalidCatch(tryNode.catchClauses)) != null) {
+      if (catchNode.onKeyword != null) {
+        if (catchNode.exceptionType.length == 0) {
+          String src = utils.getNodeText(catchNode);
+          if (src.startsWith(new RegExp(r'on[ \t]+'))) {
+            if (src.startsWith(new RegExp(r'on[ \t][ \t]+'))) {
+              // onSpaces
+              exitPosition = new Position(file, catchNode.onKeyword.end + 1);
+              sb = new SourceBuilder(file, catchNode.onKeyword.end + 2);
+              addSpace = false;
+            } else {
+              // onSpace
+              sb = new SourceBuilder(file, catchNode.onKeyword.end + 1);
+              sb.setExitOffset();
+            }
+          } else {
+            // onOnly
+            sb = new SourceBuilder(file, catchNode.onKeyword.end);
+            sb.append(' ');
+            sb.setExitOffset();
+          }
+        } else {
+          // onType
+          sb = new SourceBuilder(file, catchNode.exceptionType.end);
+        }
+      }
+      if (catchNode.catchKeyword != null) {
+        // catchOnly
+        var struct = new _KeywordConditionBlockStructure(
+            catchNode.catchKeyword,
+            catchNode.leftParenthesis,
+            catchNode.exceptionParameter,
+            catchNode.rightParenthesis,
+            catchNode.body);
+        if (sb != null) {
+          // onCatch
+          _insertBuilder(sb);
+        }
+        sb = _complete_keywordCondition(struct);
+        if (sb == null) {
+          return false;
+        }
+      }
+      if (catchNode.body.leftBracket.isSynthetic) {
+        // onOnly and others
+        if (addSpace) {
+          sb.append(' ');
+        }
+        _appendEmptyBraces(sb, exitPosition == null);
+      }
+      _insertBuilder(sb);
+    } else if (tryNode.finallyKeyword != null) {
+      if (tryNode.finallyBlock.leftBracket.isSynthetic) {
+        // finallyOnly
+        sb = new SourceBuilder(file, tryNode.finallyKeyword.end);
+        sb.append(' ');
+        _appendEmptyBraces(sb, true);
+        _insertBuilder(sb);
+      }
+    }
+    _setCompletion(DartStatementCompletion.COMPLETE_TRY_STMT);
+    return true;
   }
 
   bool _complete_whileStatement() {
     if (errors.isEmpty || node is! WhileStatement) {
       return false;
     }
     WhileStatement whileNode = node;
     if (whileNode != null) {
       var stmt = new _KeywordConditionBlockStructure(
           whileNode.whileKeyword,
@@ skipping 12 matching lines @@
         errors.firstWhere((err) => err.errorCode == code, orElse: () => null);
     if (error != null) {
       if (partialMatch != null) {
         return error.message.contains(partialMatch) ? error : null;
       }
       return error;
     }
     return null;
   }
 
+  CatchClause _firstInvalidCatch(NodeList<CatchClause> list) {
+    return list.firstWhere((e) {
+      bool found = false;
+      for (var error in errors) {
+        if (error.offset >= e.offset && error.offset <= e.end) {
+          if (error.errorCode is! HintCode) {
+            found = true;
+            break;
+          }
+        }
+      }
+      return found;
+    }, orElse: () => null);
+  }
+
   LinkedEditGroup _getLinkedPosition(String groupId) {
     LinkedEditGroup group = linkedPositionGroups[groupId];
     if (group == null) {
       group = new LinkedEditGroup.empty();
       linkedPositionGroups[groupId] = group;
     }
     return group;
   }
 
   void _insertBuilder(SourceBuilder builder, [int length = 0]) {
@@ skipping 72 matching lines @@
   final Token keyword;
   final Token leftParenthesis, rightParenthesis;
   final Expression condition;
   final Statement block;
 
   _KeywordConditionBlockStructure(this.keyword, this.leftParenthesis,
       this.condition, this.rightParenthesis, this.block);
 
   int get offset => keyword.offset;
 }