fix: Lazily create program and type checker when necessary.

Implements #188.
dsherret · Dec 21, 2017 · 77b3889 · 77b3889
1 parent 79fbf4a
commit 77b3889
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Showing 4 changed files with 19 additions and 25 deletions.
diff --git a/src/GlobalContainer.ts b/src/GlobalContainer.ts
@@ -35,7 +35,7 @@ export class GlobalContainer {
         if (opts.typeChecker != null) {
             errors.throwIfTrue(opts.createLanguageService, "Cannot specify a type checker and create a language service.");
             this._customTypeChecker = new TypeChecker(this);
-            this._customTypeChecker.reset(opts.typeChecker);
+            this._customTypeChecker.reset(() => opts.typeChecker!);
         }
     }
 

diff --git a/src/compiler/tools/LanguageService.ts b/src/compiler/tools/LanguageService.ts
@@ -80,6 +80,7 @@ export class LanguageService {
         };
 
         this._compilerObject = ts.createLanguageService(languageServiceHost);
+        this.program = new Program(this.global, this.global.compilerFactory.getSourceFilePaths(), this.compilerHost);
 
         this.global.compilerFactory.onSourceFileAdded(() => this.resetProgram());
         this.global.compilerFactory.onSourceFileRemoved(() => this.resetProgram());
@@ -90,16 +91,13 @@ export class LanguageService {
      * @internal
      */
     resetProgram() {
-        if (this.program != null)
-            this.program.reset(this.global.compilerFactory.getSourceFilePaths(), this.compilerHost);
+        this.program.reset(this.global.compilerFactory.getSourceFilePaths(), this.compilerHost);
     }
 
     /**
      * Gets the language service's program.
      */
     getProgram() {
-        if (this.program == null)
-            this.program = new Program(this.global, this.global.compilerFactory.getSourceFilePaths(), this.compilerHost);
         return this.program;
     }
 

diff --git a/src/compiler/tools/Program.ts b/src/compiler/tools/Program.ts
@@ -31,7 +31,9 @@ export class Program {
     /** @internal */
     private readonly typeChecker: TypeChecker;
     /** @internal */
-    private _compilerObject: ts.Program;
+    private _createdCompilerObject: ts.Program | undefined;
+    /** @internal */
+    private _getOrCreateCompilerObject: () => ts.Program;
 
     /** @internal */
     constructor(global: GlobalContainer, rootNames: string[], host: ts.CompilerHost) {
@@ -44,7 +46,7 @@ export class Program {
      * Gets the underlying compiler program.
      */
     get compilerObject() {
-        return this._compilerObject;
+        return this._getOrCreateCompilerObject();
     }
 
     /**
@@ -53,20 +55,14 @@ export class Program {
      */
     reset(rootNames: string[], host: ts.CompilerHost) {
         const compilerOptions = this.global.compilerOptions;
-        const oldProgram = this._compilerObject;
-        this._compilerObject = getNewProgram();
-        this.typeChecker.reset(this._compilerObject.getTypeChecker());
-
-        function getNewProgram() {
-            try {
-                // try to reuse the old compiler object
-                return ts.createProgram(rootNames, compilerOptions, host, oldProgram);
-            } catch (err) {
-                Logger.warn("Could not create new program from old program. " + err);
-                // if that fails, try without using the old program
-                return ts.createProgram(rootNames, compilerOptions, host);
-            }
-        }
+        this._getOrCreateCompilerObject = () => {
+            if (this._createdCompilerObject == null)
+                this._createdCompilerObject = ts.createProgram(rootNames, compilerOptions, host);
+            // this needs to be on a separate line in case the program was reset between the line above and here
+            return this._createdCompilerObject || this._getOrCreateCompilerObject();
+        };
+        this._createdCompilerObject = undefined;
+        this.typeChecker.reset(() => this.compilerObject.getTypeChecker());
     }
 
     /**

diff --git a/src/compiler/tools/TypeChecker.ts b/src/compiler/tools/TypeChecker.ts
@@ -11,7 +11,7 @@ export class TypeChecker {
     /** @internal */
     private readonly global: GlobalContainer;
     /** @internal */
-    private _compilerObject: ts.TypeChecker;
+    private _getCompilerObject: () => ts.TypeChecker;
 
     /** @internal */
     constructor(global: GlobalContainer) {
@@ -22,15 +22,15 @@ export class TypeChecker {
      * Gets the compiler's TypeChecker.
      */
     get compilerObject() {
-        return this._compilerObject;
+        return this._getCompilerObject();
     }
 
     /**
      * Resets the type checker.
      * @internal
      */
-    reset(typeChecker: ts.TypeChecker) {
-        this._compilerObject = typeChecker;
+    reset(getTypeChecker: () => ts.TypeChecker) {
+        this._getCompilerObject = getTypeChecker;
     }
 
     /**