From 12d3d8a7418063203b812e01aac227d58c4aeada Mon Sep 17 00:00:00 2001
From: Cyrus Najmabadi <cyrusn@microsoft.com>
Date: Tue, 4 Nov 2014 00:49:42 -0800
Subject: [PATCH] Specialize findToken walk.

---
 src/services/syntax/SyntaxGenerator.js        |  4 +-
 src/services/syntax/syntaxElement.ts          | 39 ++++++++++++++++---
 src/services/syntax/syntaxGenerator.ts        |  7 +++-
 .../syntax/syntaxUtilities.generated.ts       |  4 ++
 4 files changed, 46 insertions(+), 8 deletions(-)

diff --git a/src/services/syntax/SyntaxGenerator.js b/src/services/syntax/SyntaxGenerator.js
index b7f88fd66f6..0da69eec942 100644
--- a/src/services/syntax/SyntaxGenerator.js
+++ b/src/services/syntax/SyntaxGenerator.js
@@ -2261,7 +2261,6 @@ function generateServicesUtilities() {
         }
         result += "undefined";
     }
-    ;
     for (var i = 0; i < definitions.length; i++) {
         var definition = definitions[i];
         result += ",\r\n";
@@ -2282,6 +2281,9 @@ function generateServicesUtilities() {
     result += "    export function childAt(element: ISyntaxElement, index: number): ISyntaxElement {\r\n";
     result += "        if (isList(element)) { return (<ISyntaxNodeOrToken[]>element)[index]; }\r\n";
     result += "        return childAtArray[element.kind](element, index);\r\n";
+    result += "    }\r\n\r\n";
+    result += "    export function getChildAtFunction(element: ISyntaxNodeOrToken): (nodeOrToken: ISyntaxElement, index: number) => ISyntaxElement {\r\n";
+    result += "        return childAtArray[element.kind];\r\n";
     result += "    }\r\n";
     result += "}";
     return result;
diff --git a/src/services/syntax/syntaxElement.ts b/src/services/syntax/syntaxElement.ts
index 4fcb3276516..e42d9d44cdb 100644
--- a/src/services/syntax/syntaxElement.ts
+++ b/src/services/syntax/syntaxElement.ts
@@ -53,7 +53,7 @@ module TypeScript {
             throw Errors.argumentOutOfRange("position");
         }
 
-        var token = findTokenWorker(sourceUnit, 0, position);
+        var token = findTokenInNodeOrToken(sourceUnit, 0, position);
         if (token) {
             Debug.assert(token.fullWidth() > 0);
             return token;
@@ -113,13 +113,40 @@ module TypeScript {
     }
 
     function findTokenWorker(element: ISyntaxElement, elementPosition: number, position: number): ISyntaxToken {
-        if (isToken(element)) {
-            return <ISyntaxToken>element;
+        if (isList(element)) {
+            return findTokenInList(<ISyntaxNodeOrToken[]>element, elementPosition, position);
+        }
+        else {
+            return findTokenInNodeOrToken(<ISyntaxNodeOrToken>element, elementPosition, position);
+        }
+    }
+
+    function findTokenInList(list: ISyntaxNodeOrToken[], elementPosition: number, position: number): ISyntaxToken {
+        for (var i = 0, n = list.length; i < n; i++) {
+            var child = list[i];
+
+            var childFullWidth = fullWidth(child);
+            var elementEndPosition = elementPosition + childFullWidth;
+
+            if (position < elementEndPosition) {
+                return findTokenWorker(child, elementPosition, position);
+            }
+
+            elementPosition = elementEndPosition;
         }
 
-        // Consider: we could use a binary search here to find the child more quickly.
-        for (var i = 0, n = childCount(element); i < n; i++) {
-            var child = childAt(element, i);
+        return undefined;
+    }
+
+
+    function findTokenInNodeOrToken(nodeOrToken: ISyntaxNodeOrToken, elementPosition: number, position: number): ISyntaxToken {
+        if (isToken(nodeOrToken)) {
+            return <ISyntaxToken>nodeOrToken;
+        }
+
+        var childAtFunction = getChildAtFunction(nodeOrToken);
+        for (var i = 0, n = childCount(nodeOrToken); i < n; i++) {
+            var child = childAtFunction(nodeOrToken, i);
 
             if (child) {
                 var childFullWidth = fullWidth(child);
diff --git a/src/services/syntax/syntaxGenerator.ts b/src/services/syntax/syntaxGenerator.ts
index 68a596fe23e..a9ae6ff5d53 100644
--- a/src/services/syntax/syntaxGenerator.ts
+++ b/src/services/syntax/syntaxGenerator.ts
@@ -1534,7 +1534,7 @@ function generateServicesUtilities(): string {
             result += "0";
         }
         else {
-            var definition = TypeScript.ArrayUtilities.first(definitions,d => firstKind(d) === i);
+            var definition = TypeScript.ArrayUtilities.first(definitions, d => firstKind(d) === i);
             result += definition.children.length;
         }
     }
@@ -1609,8 +1609,13 @@ function generateServicesUtilities(): string {
     //}
 
     //result += "        }\r\n";
+    result += "    }\r\n\r\n";
+
+    result += "    export function getChildAtFunction(element: ISyntaxNodeOrToken): (nodeOrToken: ISyntaxElement, index: number) => ISyntaxElement {\r\n";
+    result += "        return childAtArray[element.kind];\r\n";
     result += "    }\r\n";
 
+
     result += "}";
 
 
diff --git a/src/services/syntax/syntaxUtilities.generated.ts b/src/services/syntax/syntaxUtilities.generated.ts
index 973c7571864..17152889f5c 100644
--- a/src/services/syntax/syntaxUtilities.generated.ts
+++ b/src/services/syntax/syntaxUtilities.generated.ts
@@ -696,4 +696,8 @@ module TypeScript {
         if (isList(element)) { return (<ISyntaxNodeOrToken[]>element)[index]; }
         return childAtArray[element.kind](element, index);
     }
+
+    export function getChildAtFunction(element: ISyntaxNodeOrToken): (nodeOrToken: ISyntaxElement, index: number) => ISyntaxElement {
+        return childAtArray[element.kind];
+    }
 }
\ No newline at end of file