From fab4ef0bdeae9d192c3efadeb7ef62fe9028d4cd Mon Sep 17 00:00:00 2001
From: Vladimir Matveev <vladima@microsoft.com>
Date: Tue, 7 Mar 2017 13:26:41 -0800
Subject: [PATCH] cache semantic and declaration diagnostics in program
 (#14516)

---
 src/compiler/program.ts | 44 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 43 insertions(+), 1 deletion(-)

diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index d9ddf486e0d..abb8b0b2f09 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -290,6 +290,11 @@ namespace ts {
         return resolutions;
     }
 
+    interface DiagnosticCache {
+        perFile?: FileMap<Diagnostic[]>;
+        allDiagnostics?: Diagnostic[];
+    }
+
     export function createProgram(rootNames: string[], options: CompilerOptions, host?: CompilerHost, oldProgram?: Program): Program {
         let program: Program;
         let files: SourceFile[] = [];
@@ -298,6 +303,9 @@ namespace ts {
         let noDiagnosticsTypeChecker: TypeChecker;
         let classifiableNames: Map<string>;
 
+        let cachedSemanticDiagnosticsForFile: DiagnosticCache = {};
+        let cachedDeclarationDiagnosticsForFile: DiagnosticCache = {};
+
         let resolvedTypeReferenceDirectives = createMap<ResolvedTypeReferenceDirective>();
         let fileProcessingDiagnostics = createDiagnosticCollection();
 
@@ -899,6 +907,10 @@ namespace ts {
         }
 
         function getSemanticDiagnosticsForFile(sourceFile: SourceFile, cancellationToken: CancellationToken): Diagnostic[] {
+            return getAndCacheDiagnostics(sourceFile, cancellationToken, cachedSemanticDiagnosticsForFile, getSemanticDiagnosticsForFileNoCache);
+        }
+
+        function getSemanticDiagnosticsForFileNoCache(sourceFile: SourceFile, cancellationToken: CancellationToken): Diagnostic[] {
             return runWithCancellationToken(() => {
                 const typeChecker = getDiagnosticsProducingTypeChecker();
 
@@ -1094,7 +1106,11 @@ namespace ts {
             });
         }
 
-        function getDeclarationDiagnosticsWorker(sourceFile: SourceFile, cancellationToken: CancellationToken): Diagnostic[] {
+        function getDeclarationDiagnosticsWorker(sourceFile: SourceFile | undefined, cancellationToken: CancellationToken): Diagnostic[] {
+            return getAndCacheDiagnostics(sourceFile, cancellationToken, cachedDeclarationDiagnosticsForFile, getDeclarationDiagnosticsForFileNoCache);
+        }
+
+        function getDeclarationDiagnosticsForFileNoCache(sourceFile: SourceFile| undefined, cancellationToken: CancellationToken) {
             return runWithCancellationToken(() => {
                 const resolver = getDiagnosticsProducingTypeChecker().getEmitResolver(sourceFile, cancellationToken);
                 // Don't actually write any files since we're just getting diagnostics.
@@ -1102,6 +1118,32 @@ namespace ts {
             });
         }
 
+        function getAndCacheDiagnostics(
+            sourceFile: SourceFile | undefined,
+            cancellationToken: CancellationToken,
+            cache: DiagnosticCache,
+            getDiagnostics: (sourceFile: SourceFile, cancellationToken: CancellationToken) => Diagnostic[]) {
+
+            const cachedResult = sourceFile
+                ? cache.perFile && cache.perFile.get(sourceFile.path)
+                : cache.allDiagnostics;
+
+            if (cachedResult) {
+                return cachedResult;
+            }
+            const result = getDiagnostics(sourceFile, cancellationToken) || emptyArray;
+            if (sourceFile) {
+                if (!cache.perFile) {
+                    cache.perFile = createFileMap<Diagnostic[]>();
+                }
+                cache.perFile.set(sourceFile.path, result);
+            }
+            else {
+                cache.allDiagnostics = result;
+            }
+            return result;
+        }
+
         function getDeclarationDiagnosticsForFile(sourceFile: SourceFile, cancellationToken: CancellationToken): Diagnostic[] {
             return isDeclarationFile(sourceFile) ? [] : getDeclarationDiagnosticsWorker(sourceFile, cancellationToken);
         }