From 7b99d47215af2f65a2c4bea9ca202c3987dc150b Mon Sep 17 00:00:00 2001
From: Rich Harris <richard.a.harris@gmail.com>
Date: Mon, 29 May 2017 13:45:18 -0400
Subject: [PATCH] add cascade option, to prevent components inheriting styles
 (#583)

---
 package.json                                  |  2 +-
 src/generators/Generator.ts                   |  6 +-
 .../dom/visitors/Element/Element.ts           |  2 +-
 src/generators/server-side-rendering/index.ts |  1 +
 .../server-side-rendering/visitors/Element.ts |  2 +-
 src/generators/shared/processCss.ts           | 76 ++++++++++++++-----
 src/interfaces.ts                             |  1 +
 test/css/index.js                             | 14 +++-
 .../expected.css                              | 13 ++++
 .../cascade-false-global-keyframes/input.html | 17 +++++
 .../samples/cascade-false-global/_config.js   |  3 +
 .../samples/cascade-false-global/expected.css | 12 +++
 .../samples/cascade-false-global/input.html   | 16 ++++
 .../cascade-false-keyframes/expected.css      | 13 ++++
 .../cascade-false-keyframes/input.html        | 17 +++++
 test/css/samples/cascade-false/_config.js     |  3 +
 test/css/samples/cascade-false/expected.css   | 12 +++
 test/css/samples/cascade-false/input.html     | 16 ++++
 18 files changed, 203 insertions(+), 23 deletions(-)
 create mode 100644 test/css/samples/cascade-false-global-keyframes/expected.css
 create mode 100644 test/css/samples/cascade-false-global-keyframes/input.html
 create mode 100644 test/css/samples/cascade-false-global/_config.js
 create mode 100644 test/css/samples/cascade-false-global/expected.css
 create mode 100644 test/css/samples/cascade-false-global/input.html
 create mode 100644 test/css/samples/cascade-false-keyframes/expected.css
 create mode 100644 test/css/samples/cascade-false-keyframes/input.html
 create mode 100644 test/css/samples/cascade-false/_config.js
 create mode 100644 test/css/samples/cascade-false/expected.css
 create mode 100644 test/css/samples/cascade-false/input.html

diff --git a/package.json b/package.json
index 584bacd2dd6b..958621042a60 100644
--- a/package.json
+++ b/package.json
@@ -66,7 +66,7 @@
     "glob": "^7.1.1",
     "jsdom": "^9.9.1",
     "locate-character": "^2.0.0",
-    "magic-string": "^0.19.0",
+    "magic-string": "^0.21.1",
     "mocha": "^3.2.0",
     "node-resolve": "^1.3.3",
     "nyc": "^10.0.0",
diff --git a/src/generators/Generator.ts b/src/generators/Generator.ts
index 9fe322e7f9e8..f09de865509f 100644
--- a/src/generators/Generator.ts
+++ b/src/generators/Generator.ts
@@ -29,8 +29,11 @@ export default class Generator {
 	transitions: Set<string>;
 	importedComponents: Map<string, string>;
 
+	code: MagicString;
+
 	bindingGroups: string[];
 	expectedProperties: Set<string>;
+	cascade: boolean;
 	css: string;
 	cssId: string;
 	usesRefs: boolean;
@@ -59,7 +62,8 @@ export default class Generator {
 		this.expectedProperties = new Set();
 
 		this.code = new MagicString( source );
-		this.css = parsed.css ? processCss( parsed, this.code ) : null;
+		this.cascade = options.cascade !== false; // TODO remove this option in v2
+		this.css = parsed.css ? processCss( parsed, this.code, this.cascade ) : null;
 		this.cssId = parsed.css ? `svelte-${parsed.hash}` : '';
 		this.usesRefs = false;
 
diff --git a/src/generators/dom/visitors/Element/Element.ts b/src/generators/dom/visitors/Element/Element.ts
index 5e831becd7e2..8ee8b7712d3c 100644
--- a/src/generators/dom/visitors/Element/Element.ts
+++ b/src/generators/dom/visitors/Element/Element.ts
@@ -46,7 +46,7 @@ export default function visitElement ( generator: DomGenerator, block: Block, st
 	block.mount( name, state.parentNode );
 
 	// add CSS encapsulation attribute
-	if ( generator.cssId && state.isTopLevel ) {
+	if ( generator.cssId && ( !generator.cascade || state.isTopLevel ) ) {
 		block.builders.create.addLine( `${generator.helper( 'setAttribute' )}( ${name}, '${generator.cssId}', '' );` );
 	}
 
diff --git a/src/generators/server-side-rendering/index.ts b/src/generators/server-side-rendering/index.ts
index 5a95b4896587..90c4e6cdf34a 100644
--- a/src/generators/server-side-rendering/index.ts
+++ b/src/generators/server-side-rendering/index.ts
@@ -13,6 +13,7 @@ export class SsrGenerator extends Generator {
 		super( parsed, source, name, options );
 		this.bindings = [];
 		this.renderCode = '';
+		this.elementDepth = 0;
 	}
 
 	append ( code: string ) {
diff --git a/src/generators/server-side-rendering/visitors/Element.ts b/src/generators/server-side-rendering/visitors/Element.ts
index 05267f6bd0d8..2c351ed680ec 100644
--- a/src/generators/server-side-rendering/visitors/Element.ts
+++ b/src/generators/server-side-rendering/visitors/Element.ts
@@ -50,7 +50,7 @@ export default function visitElement ( generator: SsrGenerator, block: Block, no
 		}
 	});
 
-	if ( generator.cssId && !generator.elementDepth ) {
+	if ( generator.cssId && ( !generator.cascade || generator.elementDepth === 0 ) ) {
 		openingTag += ` ${generator.cssId}`;
 	}
 
diff --git a/src/generators/shared/processCss.ts b/src/generators/shared/processCss.ts
index b83630d756f9..4eff6322442e 100644
--- a/src/generators/shared/processCss.ts
+++ b/src/generators/shared/processCss.ts
@@ -1,8 +1,9 @@
+import MagicString from 'magic-string';
 import { Parsed, Node } from '../../interfaces';
 
 const commentsPattern = /\/\*[\s\S]*?\*\//g;
 
-export default function processCss ( parsed: Parsed, code ) {
+export default function processCss ( parsed: Parsed, code: MagicString, cascade: boolean ) {
 	const css = parsed.css.content.styles;
 	const offset = parsed.css.content.start;
 
@@ -14,9 +15,13 @@ export default function processCss ( parsed: Parsed, code ) {
 		if ( node.type === 'Atrule' && node.name.toLowerCase() === 'keyframes' ) {
 			node.expression.children.forEach( ( expression: Node ) => {
 				if ( expression.type === 'Identifier' ) {
-					const newName = `svelte-${parsed.hash}-${expression.name}`;
-					code.overwrite( expression.start, expression.end, newName );
-					keyframes.set( expression.name, newName );
+					if ( expression.name.startsWith( '-global-' ) ) {
+						code.remove( expression.start, expression.start + 8 );
+					} else {
+						const newName = `svelte-${parsed.hash}-${expression.name}`;
+						code.overwrite( expression.start, expression.end, newName );
+						keyframes.set( expression.name, newName );
+					}
 				}
 			});
 		} else if ( node.children ) {
@@ -30,26 +35,63 @@ export default function processCss ( parsed: Parsed, code ) {
 
 	function transform ( rule: Node ) {
 		rule.selector.children.forEach( ( selector: Node ) => {
-			const start = selector.start - offset;
-			const end = selector.end - offset;
+			if ( cascade ) {
+				// TODO disable cascading (without :global(...)) in v2
+				const start = selector.start - offset;
+				const end = selector.end - offset;
 
-			const selectorString = css.slice( start, end );
+				const selectorString = css.slice( start, end );
 
-			const firstToken = selector.children[0];
+				const firstToken = selector.children[0];
 
-			let transformed;
+				let transformed;
 
-			if ( firstToken.type === 'TypeSelector' ) {
-				const insert = firstToken.end - offset;
-				const head = css.slice( start, insert );
-				const tail = css.slice( insert, end );
+				if ( firstToken.type === 'TypeSelector' ) {
+					const insert = firstToken.end - offset;
+					const head = css.slice( start, insert );
+					const tail = css.slice( insert, end );
 
-				transformed = `${head}${attr}${tail}, ${attr} ${selectorString}`;
-			} else {
-				transformed = `${attr}${selectorString}, ${attr} ${selectorString}`;
+					transformed = `${head}${attr}${tail}, ${attr} ${selectorString}`;
+				} else {
+					transformed = `${attr}${selectorString}, ${attr} ${selectorString}`;
+				}
+
+				code.overwrite( selector.start, selector.end, transformed );
 			}
 
-			code.overwrite( start + offset, end + offset, transformed );
+			else {
+				let shouldTransform = true;
+				let c = selector.start;
+
+				selector.children.forEach( ( child: Node ) => {
+					if ( child.type === 'WhiteSpace' || child.type === 'Combinator' ) {
+						code.appendLeft( c, attr );
+						shouldTransform = true;
+						return;
+					}
+
+					if ( !shouldTransform ) return;
+
+					if ( child.type === 'PseudoClassSelector' ) {
+						// `:global(xyz)` > xyz
+						if ( child.name === 'global' ) {
+							const first = child.children[0];
+							const last = child.children[child.children.length - 1];
+							code.remove( child.start, first.start ).remove( last.end, child.end );
+						} else {
+							code.prependRight( c, attr );
+						}
+
+						shouldTransform = false;
+					}
+
+					c = child.end;
+				});
+
+				if ( shouldTransform ) {
+					code.appendLeft( c, attr );
+				}
+			}
 		});
 
 		rule.block.children.forEach( ( block: Node ) => {
diff --git a/src/interfaces.ts b/src/interfaces.ts
index 2a2d88e9e2f2..0caa4d6ed13a 100644
--- a/src/interfaces.ts
+++ b/src/interfaces.ts
@@ -40,6 +40,7 @@ export interface CompileOptions {
 
 	dev?: boolean;
 	shared?: boolean | string;
+	cascade?: boolean;
 
 	onerror?: (error: Error) => void
 	onwarn?: (warning: Warning) => void
diff --git a/test/css/index.js b/test/css/index.js
index 2311a806b39d..e333a9967f49 100644
--- a/test/css/index.js
+++ b/test/css/index.js
@@ -1,6 +1,15 @@
 import assert from 'assert';
 import * as fs from 'fs';
-import { svelte, exists } from '../helpers.js';
+import { svelte } from '../helpers.js';
+
+function tryRequire ( file ) {
+	try {
+		return require( file ).default;
+	} catch ( err ) {
+		if ( err.code !== 'MODULE_NOT_FOUND' ) throw err;
+		return null;
+	}
+}
 
 describe( 'css', () => {
 	fs.readdirSync( 'test/css/samples' ).forEach( dir => {
@@ -14,9 +23,10 @@ describe( 'css', () => {
 		}
 
 		( solo ? it.only : it )( dir, () => {
+			const config = tryRequire( `./samples/${dir}/_config.js` ) || {};
 			const input = fs.readFileSync( `test/css/samples/${dir}/input.html`, 'utf-8' ).replace( /\s+$/, '' );
 
-			const actual = svelte.compile( input ).css;
+			const actual = svelte.compile( input, config ).css;
 			fs.writeFileSync( `test/css/samples/${dir}/_actual.css`, actual );
 			const expected = fs.readFileSync( `test/css/samples/${dir}/expected.css`, 'utf-8' );
 
diff --git a/test/css/samples/cascade-false-global-keyframes/expected.css b/test/css/samples/cascade-false-global-keyframes/expected.css
new file mode 100644
index 000000000000..b13c5736bec5
--- /dev/null
+++ b/test/css/samples/cascade-false-global-keyframes/expected.css
@@ -0,0 +1,13 @@
+
+	@keyframes why {
+		0% { color: red; }
+		100% { color: blue; }
+	}
+
+	[svelte-2486527405].animated, [svelte-2486527405] .animated {
+		animation: why 2s;
+	}
+
+	[svelte-2486527405].also-animated, [svelte-2486527405] .also-animated {
+		animation: not-defined-here 2s;
+	}
diff --git a/test/css/samples/cascade-false-global-keyframes/input.html b/test/css/samples/cascade-false-global-keyframes/input.html
new file mode 100644
index 000000000000..3f2d568807f7
--- /dev/null
+++ b/test/css/samples/cascade-false-global-keyframes/input.html
@@ -0,0 +1,17 @@
+<div class='animated'>animated</div>
+<div class='also-animated'>also animated</div>
+
+<style>
+	@keyframes -global-why {
+		0% { color: red; }
+		100% { color: blue; }
+	}
+
+	.animated {
+		animation: why 2s;
+	}
+
+	.also-animated {
+		animation: not-defined-here 2s;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/cascade-false-global/_config.js b/test/css/samples/cascade-false-global/_config.js
new file mode 100644
index 000000000000..b37866f9b61a
--- /dev/null
+++ b/test/css/samples/cascade-false-global/_config.js
@@ -0,0 +1,3 @@
+export default {
+	cascade: false
+};
\ No newline at end of file
diff --git a/test/css/samples/cascade-false-global/expected.css b/test/css/samples/cascade-false-global/expected.css
new file mode 100644
index 000000000000..96071a3d6ffc
--- /dev/null
+++ b/test/css/samples/cascade-false-global/expected.css
@@ -0,0 +1,12 @@
+
+	div {
+		color: red;
+	}
+
+	div.foo {
+		color: blue;
+	}
+
+	.foo {
+		font-weight: bold;
+	}
diff --git a/test/css/samples/cascade-false-global/input.html b/test/css/samples/cascade-false-global/input.html
new file mode 100644
index 000000000000..947edb6ab57d
--- /dev/null
+++ b/test/css/samples/cascade-false-global/input.html
@@ -0,0 +1,16 @@
+<div>red</div>
+<div class='foo'>bold/blue</div>
+
+<style>
+	:global(div) {
+		color: red;
+	}
+
+	:global(div.foo) {
+		color: blue;
+	}
+
+	:global(.foo) {
+		font-weight: bold;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/cascade-false-keyframes/expected.css b/test/css/samples/cascade-false-keyframes/expected.css
new file mode 100644
index 000000000000..cf1d1714172f
--- /dev/null
+++ b/test/css/samples/cascade-false-keyframes/expected.css
@@ -0,0 +1,13 @@
+
+	@keyframes svelte-776829126-why {
+		0% { color: red; }
+		100% { color: blue; }
+	}
+
+	[svelte-776829126].animated, [svelte-776829126] .animated {
+		animation: svelte-776829126-why 2s;
+	}
+
+	[svelte-776829126].also-animated, [svelte-776829126] .also-animated {
+		animation: not-defined-here 2s;
+	}
diff --git a/test/css/samples/cascade-false-keyframes/input.html b/test/css/samples/cascade-false-keyframes/input.html
new file mode 100644
index 000000000000..ba220a5e22ce
--- /dev/null
+++ b/test/css/samples/cascade-false-keyframes/input.html
@@ -0,0 +1,17 @@
+<div class='animated'>animated</div>
+<div class='also-animated'>also animated</div>
+
+<style>
+	@keyframes why {
+		0% { color: red; }
+		100% { color: blue; }
+	}
+
+	.animated {
+		animation: why 2s;
+	}
+
+	.also-animated {
+		animation: not-defined-here 2s;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/cascade-false/_config.js b/test/css/samples/cascade-false/_config.js
new file mode 100644
index 000000000000..b37866f9b61a
--- /dev/null
+++ b/test/css/samples/cascade-false/_config.js
@@ -0,0 +1,3 @@
+export default {
+	cascade: false
+};
\ No newline at end of file
diff --git a/test/css/samples/cascade-false/expected.css b/test/css/samples/cascade-false/expected.css
new file mode 100644
index 000000000000..0a9cb4502e53
--- /dev/null
+++ b/test/css/samples/cascade-false/expected.css
@@ -0,0 +1,12 @@
+
+	div[svelte-4161687011] {
+		color: red;
+	}
+
+	div.foo[svelte-4161687011] {
+		color: blue;
+	}
+
+	.foo[svelte-4161687011] {
+		font-weight: bold;
+	}
diff --git a/test/css/samples/cascade-false/input.html b/test/css/samples/cascade-false/input.html
new file mode 100644
index 000000000000..f56b586ef8b2
--- /dev/null
+++ b/test/css/samples/cascade-false/input.html
@@ -0,0 +1,16 @@
+<div>red</div>
+<div class='foo'>bold/blue</div>
+
+<style>
+	div {
+		color: red;
+	}
+
+	div.foo {
+		color: blue;
+	}
+
+	.foo {
+		font-weight: bold;
+	}
+</style>
\ No newline at end of file