From d98a9a0150b4b363b27c44eb336443b02581112f Mon Sep 17 00:00:00 2001
From: Ryan Cavanaugh <RyanCavanaugh@users.noreply.github.com>
Date: Mon, 14 May 2018 18:27:52 -0700
Subject: [PATCH] WIP

---
 src/compiler/tsbuild.ts    | 69 ++++++++++++++++++++++++++++++++++++++
 src/compiler/tsconfig.json |  3 +-
 2 files changed, 71 insertions(+), 1 deletion(-)
 create mode 100644 src/compiler/tsbuild.ts

diff --git a/src/compiler/tsbuild.ts b/src/compiler/tsbuild.ts
new file mode 100644
index 00000000000..ee41584d1fe
--- /dev/null
+++ b/src/compiler/tsbuild.ts
@@ -0,0 +1,69 @@
+namespace ts {
+/*
+    interface BuildContext {
+        unchangedOutputs: FileMap<number>;
+    }
+
+
+
+    interface FileMap<T> {
+        setValue(fileName: string, value: T): void;
+        getValue(fileName: string): T | never;
+        getValueOrUndefined(fileName: string): T | undefined;
+        getValueOrDefault(fileName: string, defaultValue: T): T;
+        tryGetValue(fileName: string): [false, undefined] | [true, T];
+    }
+
+    function createFileMap<T>(): FileMap<T> {
+        const lookup: { [key: string]: T } = Object.create(null);
+
+        return {
+            setValue,
+            getValue,
+            getValueOrUndefined,
+            getValueOrDefault,
+            tryGetValue
+        }
+
+        function setValue(fileName: string, value: T) {
+            lookup[normalizePath(fileName)] = value;
+        }
+
+        function getValue(fileName: string): T | never {
+            const f = normalizePath(fileName);
+            if (f in lookup) {
+                return lookup[f];
+            } else {
+                throw new Error(`No value corresponding to ${fileName} exists in this map`);
+            }
+        }
+
+        function getValueOrUndefined(fileName: string): T | undefined {
+            const f = normalizePath(fileName);
+            if (f in lookup) {
+                return lookup[f];
+            } else {
+                return undefined;
+            }
+        }
+
+        function getValueOrDefault(fileName: string, defaultValue: T): T {
+            const f = normalizePath(fileName);
+            if (f in lookup) {
+                return lookup[f];
+            } else {
+                return defaultValue;
+            }
+        }
+
+        function tryGetValue(fileName: string): [false, undefined] | [true, T] {
+            const f = normalizePath(fileName);
+            if (f in lookup) {
+                return [true as true, lookup[f]];
+            } else {
+                return [false as false, undefined];
+            }
+        }
+    }
+    */
+}
diff --git a/src/compiler/tsconfig.json b/src/compiler/tsconfig.json
index 46e5384434a..0db027d555f 100644
--- a/src/compiler/tsconfig.json
+++ b/src/compiler/tsconfig.json
@@ -46,6 +46,7 @@
         "resolutionCache.ts",
         "watch.ts",
         "commandLineParser.ts",
-        "tsc.ts"
+        "tsc.ts",
+        "tsbuild.ts"
     ]
 }