diff --git a/src/server/scriptInfo.ts b/src/server/scriptInfo.ts
index ce1de6f5040..4d73fc47403 100644
--- a/src/server/scriptInfo.ts
+++ b/src/server/scriptInfo.ts
@@ -16,7 +16,7 @@ namespace ts.server {
 
         public getVersion() {
             return this.svc
-                ? `SVC-${this.svcVersion}-${this.svc.getSnapshot().version}`
+                ? `SVC-${this.svcVersion}-${this.svc.getSnapshotVersion()}`
                 : `Text-${this.textVersion}`;
         }
 
@@ -62,22 +62,19 @@ namespace ts.server {
         }
 
         public getLineInfo(line: number): AbsolutePositionAndLineText {
-            return this.switchToScriptVersionCache().getSnapshot().index.lineNumberToInfo(line);
+            return this.switchToScriptVersionCache().getLineInfo(line);
         }
         /**
          *  @param line 0 based index
          */
-        lineToTextSpan(line: number) {
+        lineToTextSpan(line: number): TextSpan {
             if (!this.svc) {
                 const lineMap = this.getLineMap();
                 const start = lineMap[line]; // -1 since line is 1-based
                 const end = line + 1 < lineMap.length ? lineMap[line + 1] : this.text.length;
                 return createTextSpanFromBounds(start, end);
             }
-            const index = this.svc.getSnapshot().index;
-            const { lineText, absolutePosition } = index.lineNumberToInfo(line + 1);
-            const len = lineText !== undefined ? lineText.length : index.absolutePositionOfStartOfLine(line + 2) - absolutePosition;
-            return createTextSpan(absolutePosition, len);
+            return this.svc.lineToTextSpan(line);
         }
 
         /**
@@ -90,7 +87,7 @@ namespace ts.server {
             }
 
             // TODO: assert this offset is actually on the line
-            return this.svc.getSnapshot().index.absolutePositionOfStartOfLine(line) + (offset - 1);
+            return this.svc.lineOffsetToPosition(line, offset);
         }
 
         positionToLineOffset(position: number): protocol.Location {
@@ -98,7 +95,7 @@ namespace ts.server {
                 const { line, character } = computeLineAndCharacterOfPosition(this.getLineMap(), position);
                 return { line: line + 1, offset: character + 1 };
             }
-            return this.svc.getSnapshot().index.positionToLineOffset(position);
+            return this.svc.positionToLineOffset(position);
         }
 
         private getFileText(tempFileName?: string) {
diff --git a/src/server/scriptVersionCache.ts b/src/server/scriptVersionCache.ts
index b6a189904db..e4b41835263 100644
--- a/src/server/scriptVersionCache.ts
+++ b/src/server/scriptVersionCache.ts
@@ -5,7 +5,7 @@
 namespace ts.server {
     const lineCollectionCapacity = 4;
 
-    export interface LineCollection {
+    interface LineCollection {
         charCount(): number;
         lineCount(): number;
         isLeaf(): this is LineLeaf;
@@ -17,7 +17,7 @@ namespace ts.server {
         lineText: string | undefined;
     }
 
-    export enum CharRangeSection {
+    const enum CharRangeSection {
         PreStart,
         Start,
         Entire,
@@ -26,7 +26,7 @@ namespace ts.server {
         PostEnd
     }
 
-    export interface ILineIndexWalker {
+    interface ILineIndexWalker {
         goSubtree: boolean;
         done: boolean;
         leaf(relativeStart: number, relativeLength: number, lineCollection: LineLeaf): void;
@@ -243,7 +243,7 @@ namespace ts.server {
     }
 
     // text change information
-    export class TextChange {
+    class TextChange {
         constructor(public pos: number, public deleteLen: number, public insertedText?: string) {
         }
 
@@ -285,17 +285,6 @@ namespace ts.server {
             }
         }
 
-        latest() {
-            return this.versions[this.currentVersionToIndex()];
-        }
-
-        latestVersion() {
-            if (this.changes.length > 0) {
-                this.getSnapshot();
-            }
-            return this.currentVersion;
-        }
-
         // reload whole script, leaving no change history behind reload
         reload(script: string) {
             this.currentVersion++;
@@ -314,7 +303,9 @@ namespace ts.server {
             this.minVersion = this.currentVersion;
         }
 
-        getSnapshot() {
+        getSnapshot(): IScriptSnapshot { return this._getSnapshot(); }
+
+        private _getSnapshot(): LineIndexSnapshot {
             let snap = this.versions[this.currentVersionToIndex()];
             if (this.changes.length > 0) {
                 let snapIndex = snap.index;
@@ -334,6 +325,29 @@ namespace ts.server {
             return snap;
         }
 
+        getSnapshotVersion(): number {
+            return this._getSnapshot().version;
+        }
+
+        getLineInfo(line: number): AbsolutePositionAndLineText {
+            return this._getSnapshot().index.lineNumberToInfo(line);
+        }
+
+        lineOffsetToPosition(line: number, column: number): number {
+            return this._getSnapshot().index.absolutePositionOfStartOfLine(line) + (column - 1);
+        }
+
+        positionToLineOffset(position: number): protocol.Location {
+            return this._getSnapshot().index.positionToLineOffset(position);
+        }
+
+        lineToTextSpan(line: number): TextSpan {
+            const index = this._getSnapshot().index;
+            const { lineText, absolutePosition } = index.lineNumberToInfo(line + 1);
+            const len = lineText !== undefined ? lineText.length : index.absolutePositionOfStartOfLine(line + 2) - absolutePosition;
+            return createTextSpan(absolutePosition, len);
+        }
+
         getTextChangesBetweenVersions(oldVersion: number, newVersion: number) {
             if (oldVersion < newVersion) {
                 if (oldVersion >= this.minVersion) {
@@ -365,7 +379,7 @@ namespace ts.server {
         }
     }
 
-    export class LineIndexSnapshot implements IScriptSnapshot {
+    class LineIndexSnapshot implements IScriptSnapshot {
         constructor(readonly version: number, readonly cache: ScriptVersionCache, readonly index: LineIndex, readonly changesSincePreviousVersion: ReadonlyArray<TextChange> = emptyArray) {
         }
 
@@ -389,6 +403,7 @@ namespace ts.server {
         }
     }
 
+    /* @internal */
     export class LineIndex {
         root: LineNode;
         // set this to true to check each edit for accuracy
@@ -561,7 +576,7 @@ namespace ts.server {
         }
     }
 
-    export class LineNode implements LineCollection {
+    class LineNode implements LineCollection {
         totalChars = 0;
         totalLines = 0;
 
@@ -844,7 +859,7 @@ namespace ts.server {
         }
     }
 
-    export class LineLeaf implements LineCollection {
+    class LineLeaf implements LineCollection {
         constructor(public text: string) {
         }