Merge pull request #658 from rollup/incremental-transform

WIP: Add incremental support build by passing previous bundle

src/Bundle.js

@@ -19,6 +19,13 @@ import { dirname, isRelative, isAbsolute, relative, resolve } from './utils/path
 
 export default class Bundle {
 	constructor ( options ) {
+		this.cachedModules = new Map();
+		if ( options.cache ) {
+			options.cache.modules.forEach( module => {
+				this.cachedModules.set( module.id, module );
+			});
+		}
+
 		this.plugins = ensureArray( options.plugins );
 
 		this.plugins.forEach( plugin => {
@@ -181,7 +188,20 @@ export default class Bundle {
 
 				throw new Error( `Error loading ${id}: load hook should return a string, a { code, map } object, or nothing/null` );
 			})
-			.then( source => transform( source, id, this.transformers ) )
+			.then( source => {
+				if ( typeof source === 'string' ) {
+					source = {
+						code: source,
+						ast: null
+					};
+				}
+
+				if ( this.cachedModules.has( id ) && this.cachedModules.get( id ).originalCode === source.code ) {
+					return this.cachedModules.get( id );
+				}
+
+				return transform( source, id, this.transformers );
+			})
 			.then( source => {
 				const { code, originalCode, ast, sourceMapChain } = source;
 

src/Module.js

@@ -53,7 +53,8 @@ export default class Module {
 		}
 
 		this.comments = [];
-		this.statements = this.parse( ast );
+		this.ast = ast;
+		this.statements = this.parse();
 
 		this.declarations = blank();
 		this.analyse();
@@ -298,13 +299,13 @@ export default class Module {
 		return this.declarations['*'];
 	}
 
-	parse ( ast ) {
+	parse () {
 		// The ast can be supplied programmatically (but usually won't be)
-		if ( !ast ) {
+		if ( !this.ast ) {
 			// Try to extract a list of top-level statements/declarations. If
 			// the parse fails, attach file info and abort
 			try {
-				ast = parse( this.code, {
+				this.ast = parse( this.code, {
 					ecmaVersion: 6,
 					sourceType: 'module',
 					onComment: ( block, text, start, end ) => this.comments.push({ block, text, start, end }),
@@ -318,7 +319,7 @@ export default class Module {
 			}
 		}
 
-		walk( ast, {
+		walk( this.ast, {
 			enter: node => {
 				// eliminate dead branches early
 				if ( node.type === 'IfStatement' ) {
@@ -354,7 +355,7 @@ export default class Module {
 		let lastChar = 0;
 		let commentIndex = 0;
 
-		ast.body.forEach( node => {
+		this.ast.body.forEach( node => {
 			if ( node.type === 'EmptyStatement' ) return;
 
 			if (
@@ -637,6 +638,16 @@ export default class Module {
 		return marked;
 	}
 
+	toJSON () {
+		return {
+			id: this.id,
+			code: this.code,
+			originalCode: this.originalCode,
+			ast: this.ast,
+			sourceMapChain: this.sourceMapChain
+		};
+	}
+
 	trace ( name ) {
 		if ( name in this.declarations ) return this.declarations[ name ];
 		if ( name in this.imports ) {

src/rollup.js

@@ -9,6 +9,7 @@ export const VERSION = '<@VERSION@>';
 
 const ALLOWED_KEYS = [
 	'banner',
+	'cache',
 	'dest',
 	'entry',
 	'exports',
@@ -52,9 +53,7 @@ export function rollup ( options ) {
 		return {
 			imports: bundle.externalModules.map( module => module.id ),
 			exports: keys( bundle.entryModule.exports ),
-			modules: bundle.orderedModules.map( module => {
-				return { id: module.id };
-			}),
+			modules: bundle.orderedModules.map( module => module.toJSON() ),
 
 			generate: options => bundle.render( options ),
 			write: options => {

src/utils/transform.js

@@ -1,13 +1,6 @@
 export default function transform ( source, id, transformers ) {
 	let sourceMapChain = [];
 
-	if ( typeof source === 'string' ) {
-		source = {
-			code: source,
-			ast: null
-		};
-	}
-
 	let originalCode = source.code;
 	let ast = source.ast;
 

test/test.js

@@ -13,6 +13,7 @@ var FUNCTION = path.resolve( __dirname, 'function' );
 var FORM = path.resolve( __dirname, 'form' );
 var SOURCEMAPS = path.resolve( __dirname, 'sourcemaps' );
 var CLI = path.resolve( __dirname, 'cli' );
+var INCREMENTAL = path.resolve( __dirname, 'incremental' );
 
 var PROFILES = [
 	{ format: 'amd' },
@@ -430,7 +431,7 @@ describe( 'rollup', function () {
 							});
 							done( error );
 						}
-						
+
 						else {
 							var expected = sander.readFileSync( '_expected.js' ).toString();
 							try {
@@ -445,4 +446,82 @@ describe( 'rollup', function () {
 			});
 		});
 	});
+
+	describe.only('incremental', function () {
+		function executeBundle ( bundle ) {
+			const cjs = bundle.generate({ format: 'cjs' });
+			const m = new Function( 'module', 'exports', cjs.code );
+
+			let module = { exports: {} };
+			m( module, module.exports );
+
+			return module.exports;
+		}
+
+		var calls;
+		var modules;
+
+		var plugin = {
+			resolveId: id => id,
+
+			load: id => {
+				return modules[ id ];
+			},
+
+			transform: function ( code ) {
+				calls += 1;
+				return code;
+			}
+		};
+
+		beforeEach( () => {
+			calls = 0;
+
+			modules = {
+				entry: `import foo from 'foo'; export default foo;`,
+				foo: `export default 42`
+			};
+		});
+
+		it('does not transforms in the second time', function () {
+			return rollup.rollup({
+				entry: 'entry',
+				plugins: [ plugin ]
+			}).then( bundle => {
+				assert.equal( calls, 2 );
+				return rollup.rollup({
+					entry: 'entry',
+					plugins: [ plugin ],
+					cache: bundle
+				});
+			}).then( bundle => {
+				assert.equal( calls, 2 );
+				assert.equal( executeBundle( bundle ), 42 );
+			});
+		});
+
+		it('transforms modified sources', function () {
+			let cache;
+
+			return rollup.rollup({
+				entry: 'entry',
+				plugins: [ plugin ]
+			}).then( bundle => {
+				assert.equal( calls, 2 );
+				assert.equal( executeBundle( bundle ), 42 );
+
+				modules.foo = `export default 43`;
+				cache = bundle;
+			}).then( () => {
+				return rollup.rollup({
+					entry: 'entry',
+					plugins: [ plugin ],
+					cache
+				});
+			}).then( bundle => {
+				assert.equal( calls, 3 );
+				assert.equal( executeBundle( bundle ), 43 );
+			});
+		});
+	});
 });