1 files changed, 204 insertions, 0 deletions
diff --git a/tools/eslint/lib/rules/brace-style.js b/tools/eslint/lib/rules/brace-style.js
new file mode 100644
index 0000000000..599e86f68b
--- /dev/null
+++ b/tools/eslint/lib/rules/brace-style.js
@@ -0,0 +1,204 @@
+/**
+ * @fileoverview Rule to flag block statements that do not use the one true brace style
+ * @author Ian Christian Myers
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = function(context) {
+    var style = context.options[0] || "1tbs";
+    var params = context.options[1] || {};
+
+    var OPEN_MESSAGE = "Opening curly brace does not appear on the same line as controlling statement.",
+        BODY_MESSAGE = "Statement inside of curly braces should be on next line.",
+        CLOSE_MESSAGE = "Closing curly brace does not appear on the same line as the subsequent block.",
+        CLOSE_MESSAGE_SINGLE = "Closing curly brace should be on the same line as opening curly brace or on the line after the previous block.",
+        CLOSE_MESSAGE_STROUSTRUP = "Closing curly brace appears on the same line as the subsequent block.";
+
+    //--------------------------------------------------------------------------
+    // Helpers
+    //--------------------------------------------------------------------------
+
+    /**
+     * Determines if a given node is a block statement.
+     * @param {ASTNode} node The node to check.
+     * @returns {boolean} True if the node is a block statement, false if not.
+     * @private
+     */
+    function isBlock(node) {
+        return node && node.type === "BlockStatement";
+    }
+
+
+    /**
+     * Binds a list of properties to a function that verifies that the opening
+     * curly brace is on the same line as its controlling statement of a given
+     * node.
+     * @param {...string} The properties to check on the node.
+     * @returns {Function} A function that will perform the check on a node
+     * @private
+     */
+    function checkBlock() {
+        var blockProperties = arguments;
+
+        return function(node) {
+            [].forEach.call(blockProperties, function(blockProp) {
+                var block = node[blockProp], previousToken, curlyToken, curlyTokenEnd, curlyTokensOnSameLine;
+                block = node[blockProp];
+
+                if (isBlock(block)) {
+
+                    previousToken = context.getTokenBefore(block);
+                    curlyToken = context.getFirstToken(block);
+                    curlyTokenEnd = context.getLastToken(block);
+                    curlyTokensOnSameLine = curlyToken.loc.start.line === curlyTokenEnd.loc.start.line;
+
+                    if (previousToken.loc.start.line !== curlyToken.loc.start.line) {
+                        context.report(node, OPEN_MESSAGE);
+                    } else if (block.body.length && params.allowSingleLine) {
+
+                        if (curlyToken.loc.start.line === block.body[0].loc.start.line && !curlyTokensOnSameLine) {
+                            context.report(block.body[0], BODY_MESSAGE);
+                        } else if (curlyTokenEnd.loc.start.line === block.body[block.body.length - 1].loc.start.line && !curlyTokensOnSameLine) {
+                            context.report(block.body[block.body.length - 1], CLOSE_MESSAGE_SINGLE);
+                        }
+
+                    } else if (block.body.length && curlyToken.loc.start.line === block.body[0].loc.start.line) {
+                        context.report(block.body[0], BODY_MESSAGE);
+                    }
+                }
+            });
+        };
+    }
+
+    /**
+     * Enforces the configured brace style on IfStatements
+     * @param {ASTNode} node An IfStatement node.
+     * @returns {void}
+     * @private
+     */
+    function checkIfStatement(node) {
+        var tokens,
+            alternateIsBlock = false,
+            alternateIsIfBlock = false;
+
+        checkBlock("consequent", "alternate")(node);
+
+        if (node.alternate) {
+
+            alternateIsBlock = isBlock(node.alternate);
+            alternateIsIfBlock = node.alternate.type === "IfStatement" && isBlock(node.alternate.consequent);
+
+            if (alternateIsBlock || alternateIsIfBlock) {
+                tokens = context.getTokensBefore(node.alternate, 2);
+
+                if (style === "1tbs") {
+                    if (tokens[0].loc.start.line !== tokens[1].loc.start.line) {
+                        context.report(node.alternate, CLOSE_MESSAGE);
+                    }
+                } else if (style === "stroustrup") {
+                    if (tokens[0].loc.start.line === tokens[1].loc.start.line) {
+                        context.report(node.alternate, CLOSE_MESSAGE_STROUSTRUP);
+                    }
+                }
+            }
+
+        }
+    }
+
+    /**
+     * Enforces the configured brace style on TryStatements
+     * @param {ASTNode} node A TryStatement node.
+     * @returns {void}
+     * @private
+     */
+    function checkTryStatement(node) {
+        var tokens;
+
+        checkBlock("block", "finalizer")(node);
+
+        if (isBlock(node.finalizer)) {
+            tokens = context.getTokensBefore(node.finalizer, 2);
+            if (style === "1tbs") {
+                if (tokens[0].loc.start.line !== tokens[1].loc.start.line) {
+                    context.report(node.finalizer, CLOSE_MESSAGE);
+                }
+            } else if (style === "stroustrup") {
+                if (tokens[0].loc.start.line === tokens[1].loc.start.line) {
+                    context.report(node.finalizer, CLOSE_MESSAGE_STROUSTRUP);
+                }
+            }
+        }
+    }
+
+    /**
+     * Enforces the configured brace style on CatchClauses
+     * @param {ASTNode} node A CatchClause node.
+     * @returns {void}
+     * @private
+     */
+    function checkCatchClause(node) {
+        var previousToken = context.getTokenBefore(node),
+            firstToken = context.getFirstToken(node);
+
+        checkBlock("body")(node);
+
+        if (isBlock(node.body)) {
+            if (style === "1tbs") {
+                if (previousToken.loc.start.line !== firstToken.loc.start.line) {
+                    context.report(node, CLOSE_MESSAGE);
+                }
+            } else if (style === "stroustrup") {
+                if (previousToken.loc.start.line === firstToken.loc.start.line) {
+                    context.report(node, CLOSE_MESSAGE_STROUSTRUP);
+                }
+            }
+        }
+    }
+
+    /**
+     * Enforces the configured brace style on SwitchStatements
+     * @param {ASTNode} node A SwitchStatement node.
+     * @returns {void}
+     * @private
+     */
+    function checkSwitchStatement(node) {
+        var tokens;
+        if (node.cases && node.cases.length) {
+            tokens = context.getTokensBefore(node.cases[0], 2);
+            if (tokens[0].loc.start.line !== tokens[1].loc.start.line) {
+                context.report(node, OPEN_MESSAGE);
+            }
+        } else {
+            tokens = context.getLastTokens(node, 3);
+            if (tokens[0].loc.start.line !== tokens[1].loc.start.line) {
+                context.report(node, OPEN_MESSAGE);
+            }
+        }
+    }
+
+    //--------------------------------------------------------------------------
+    // Public API
+    //--------------------------------------------------------------------------
+
+    return {
+        "FunctionDeclaration": checkBlock("body"),
+        "FunctionExpression": checkBlock("body"),
+        "ArrowFunctionExpression": checkBlock("body"),
+        "IfStatement": checkIfStatement,
+        "TryStatement": checkTryStatement,
+        "CatchClause": checkCatchClause,
+        "DoWhileStatement": checkBlock("body"),
+        "WhileStatement": checkBlock("body"),
+        "WithStatement": checkBlock("body"),
+        "ForStatement": checkBlock("body"),
+        "ForInStatement": checkBlock("body"),
+        "ForOfStatement": checkBlock("body"),
+        "SwitchStatement": checkSwitchStatement
+    };
+
+};