Add incremental to normal tsc

Author: sheetalkamat

src/compiler/tsbuild.ts

@@ -1233,13 +1233,7 @@ namespace ts {
         function getOldProgram(proj: ResolvedConfigFileName, parsed: ParsedCommandLine) {
             const value = builderPrograms.getValue(proj);
             if (value) return value;
-            const buildInfoPath = getOutputPathForBuildInfo(parsed.options);
-            if (!buildInfoPath) return undefined;
-            const content = readFileWithCache(buildInfoPath);
-            if (!content) return undefined;
-            const buildInfo = getBuildInfo(content);
-            if (buildInfo.version !== version) return undefined;
-            return buildInfo.program && createBuildProgramUsingProgramBuildInfo(buildInfo.program) as any as T;
+            return readBuilderProgram(parsed.options, readFileWithCache) as any as T;
         }
 
         function updateBundle(proj: ResolvedConfigFileName): BuildResultFlags {

src/compiler/watch.ts

@@ -371,6 +371,19 @@ namespace ts {
         host.projectReferences = projectReferences;
         return host;
     }
+
+    export function readBuilderProgram(compilerOptions: CompilerOptions, readFile: (path: string) => string | undefined) {
+        if (compilerOptions.out || compilerOptions.outFile) return undefined;
+        if (!isIncrementalCompilation(compilerOptions)) return undefined;
+        const buildInfoPath = getOutputPathForBuildInfo(compilerOptions);
+        if (!buildInfoPath) return undefined;
+        const content = readFile(buildInfoPath);
+        if (!content) return undefined;
+        const buildInfo = getBuildInfo(content);
+        if (buildInfo.version !== version) return undefined;
+        if (!buildInfo.program) return undefined;
+        return createBuildProgramUsingProgramBuildInfo(buildInfo.program);
+    }
 }
 
 namespace ts {
@@ -645,7 +658,7 @@ namespace ts {
             ((typeDirectiveNames, containingFile, redirectedReference) => resolutionCache.resolveTypeReferenceDirectives(typeDirectiveNames, containingFile, redirectedReference));
         const userProvidedResolution = !!host.resolveModuleNames || !!host.resolveTypeReferenceDirectives;
 
-        readBuilderProgram();
+        readBuilderProgram(compilerOptions, path => compilerHost.readFile(path));
         synchronizeProgram();
 
         // Update the wild card directory watch
@@ -677,18 +690,6 @@ namespace ts {
             }
         }
 
-        function readBuilderProgram() {
-            if (compilerOptions.out || compilerOptions.outFile) return;
-            if (!isIncrementalCompilation(compilerOptions)) return;
-            const buildInfoPath = getOutputPathForBuildInfo(compilerOptions);
-            if (!buildInfoPath) return;
-            const content = directoryStructureHost.readFile(buildInfoPath);
-            if (!content) return;
-            const buildInfo = JSON.parse(content) as BuildInfo;
-            if (!buildInfo.program) return;
-            builderProgram = createBuildProgramUsingProgramBuildInfo(buildInfo.program) as any as T;
-        }
-
         function getCurrentBuilderProgram() {
             return builderProgram;
         }

src/tsc/tsc.ts

@@ -147,6 +147,9 @@ namespace ts {
                 reportWatchModeWithoutSysSupport();
                 createWatchOfConfigFile(configParseResult, commandLineOptions);
             }
+            else if (isIncrementalCompilation(configParseResult.options)) {
+                performIncrementalCompilation(configParseResult);
+            }
             else {
                 performCompilation(configParseResult.fileNames, configParseResult.projectReferences, configParseResult.options, getConfigFileParsingDiagnostics(configParseResult));
             }
@@ -254,6 +257,44 @@ namespace ts {
         return sys.exit(exitStatus);
     }
 
+    function performIncrementalCompilation(config: ParsedCommandLine) {
+        const { options, fileNames, projectReferences } = config;
+        const host = createCompilerHost(options);
+        const currentDirectory = host.getCurrentDirectory();
+        const getCanonicalFileName = createGetCanonicalFileName(host.useCaseSensitiveFileNames());
+        changeCompilerHostLikeToUseCache(host, fileName => toPath(fileName, currentDirectory, getCanonicalFileName));
+        enableStatistics(options);
+        const oldProgram = readBuilderProgram(options, path => host.readFile(path));
+        const configFileParsingDiagnostics = getConfigFileParsingDiagnostics(config);
+        const programOptions: CreateProgramOptions = {
+            rootNames: fileNames,
+            options,
+            projectReferences,
+            host,
+            configFileParsingDiagnostics: getConfigFileParsingDiagnostics(config),
+        };
+        const program = createProgram(programOptions);
+        const builderProgram = createEmitAndSemanticDiagnosticsBuilderProgram(
+            program,
+            {
+                useCaseSensitiveFileNames: () => sys.useCaseSensitiveFileNames,
+                createHash: maybeBind(sys, sys.createHash),
+                writeFile: (path, data, writeByteOrderMark) => sys.writeFile(path, data, writeByteOrderMark)
+            },
+            oldProgram,
+            configFileParsingDiagnostics
+        );
+
+        const exitStatus = emitFilesAndReportErrors(
+            builderProgram,
+            reportDiagnostic,
+            s => sys.write(s + sys.newLine),
+            createReportErrorSummary(options)
+        );
+        reportStatistics(program);
+        return sys.exit(exitStatus);
+    }
+
     function updateCreateProgram<T extends BuilderProgram>(host: { createProgram: CreateProgram<T>; }) {
         const compileUsingBuilder = host.createProgram;
         host.createProgram = (rootNames, options, host, oldProgram, configFileParsingDiagnostics, projectReferences) => {