Merge pull request #12 from Zosoled/legal-comments

Implement legal comment preservation option.

Author: vanruesc

README.md

@@ -33,6 +33,7 @@ build({
 |--------|-------------|---------|
 | minify | Enables or disables basic shader minification. | `false` |
 | resolveIncludes | When enabled, shaders can include other shaders with the custom `#include "path"` directive. | `true`  |
+| legalComments | When enabled, preserves comments starting with `//!` or `/*!` and comments containing `@license` or `@preserve`. | `false` |
 
 ### TypeScript
 

src/index.ts

@@ -25,6 +25,16 @@ export interface GLSLOptions {
 
 	resolveIncludes?: boolean;
 
+	/**
+	 * Enables or disables shader legal comment preservation.
+	 * When enabled, comments starting with `//!` or `/*!`, or comments with the
+	 * text `@license` or `@preserve`, will be preserved.
+	 *
+	 * Default is `false`.
+	 */
+
+	legalComments?: boolean;
+
 }
 
 /**
@@ -34,7 +44,7 @@ export interface GLSLOptions {
  * @return The plugin.
  */
 
-function glsl({ minify = false, resolveIncludes = true }: GLSLOptions = {}): Plugin {
+function glsl({ minify = false, resolveIncludes = true, legalComments = false }: GLSLOptions = {}): Plugin {
 
 	const cache = new Map<string, string>();
 
@@ -47,7 +57,7 @@ function glsl({ minify = false, resolveIncludes = true }: GLSLOptions = {}): Plu
 				const { contents, warnings, watchFiles } = await load(args.path, cache, resolveIncludes);
 
 				return {
-					contents: minify ? minifyShader(contents as string) : contents,
+					contents: minify ? minifyShader(contents as string, legalComments) : contents,
 					warnings,
 					watchFiles,
 					loader: "text"

src/minifyShader.ts

@@ -7,13 +7,26 @@
  * @return The minified code.
  */
 
-export function minifyShader(source: string): string {
+export function minifyShader(source: string, legalComments: boolean): string {
 
 	const commentsRegExp = /[ \t]*(?:(?:\/\*[\s\S]*?\*\/)|(?:\/\/.*\n))/g;
 	const symbolsRegExp = /\s*([{}=*,+/><&|[\]()\\!?:;-])\s*/g;
 	const genericsRegExp = /(\w<\w+>)\s*(\w)/g;
+	let preservedLegalComments: { comment: string; placeholder: string; }[] = [];
+
+	let result = source.replace(/\r/g, "");
+
+	// Preserve legal comments to be restored at the end, if requested
+	if(legalComments) {
+
+		const preserved = preserveLegalComments(result);
+		result = preserved.text;
+		preservedLegalComments = preserved.comments;
+
+	}
+
+	result = result.replace(commentsRegExp, "");
 
-	let result = source.replace(/\r/g, "").replace(commentsRegExp, "");
 	let separatedBySymbol = true;
 	let wrap = false;
 
@@ -59,6 +72,51 @@ export function minifyShader(source: string): string {
 
 	}, []).join("");
 
+	// Restore preserved legal comments, if requested
+	if(legalComments) {
+
+		for(const legalComment of preservedLegalComments) {
+
+			result = result.replace(legalComment.placeholder, `\n${legalComment.comment}`);
+
+		}
+
+	}
+
+
 	return result.replace(/\n{2,}/g, "\n");
 
 }
+
+// Finds legal comments and replaces them with placeholder text
+function preserveLegalComments(text: string) {
+
+	const legalComments = [];
+
+	// Get all statement-level comments
+	const comments = text.matchAll(/^[ \t]*(?:(?:\/\/.*$)|(?:\/\*[\s\S]*?\*\/$))/gm);
+
+	let i = 0;
+
+	for(const comment of comments) {
+
+		if(/^[ \t]*\/[/*]!/gm.test(comment[0]) || comment[0].includes("@license") || comment[0].includes("@preserve")) {
+
+			const placeholder = `__LEGAL_COMMENT_${i}__`;
+			legalComments.push({
+				"comment": comment[0],
+				placeholder
+			});
+			text = text.replace(comment[0], placeholder);
+			i++;
+
+		}
+
+	}
+
+	return {
+		text,
+		comments: legalComments
+	};
+
+}

test/expected/wgsl-legal.min.js

@@ -51,3 +51,10 @@ fn fragmentMain(
 	return vec4(surfaceColor, baseColor.a);
 
 }
+
+//! This is a single-line legal comment
+/*!
+* This is a multi-line legal comment.
+*/
+// @license This is a comment that specifies a license.
+// @preserve This is a comment that should be preserved.

test/src/shader.wgsl

@@ -96,3 +96,27 @@ test("can use include", async(t) => {
 	});
 
 });
+
+test("can preserve legal comments", async(t) => {
+
+	const config = {
+		entryPoints: ["test/src/wgsl.ts"],
+		outfile: "test/generated/wgsl-legal.min.js",
+		platform: "node",
+		format: "esm",
+		bundle: true,
+		minify: true,
+		legalComments: "inline",
+		plugins: [glsl({ minify: true, legalComments: true })]
+	};
+
+	return build(config).then(async() => {
+
+		const actual = await readFile("test/generated/wgsl-legal.min.js", "utf8");
+		const expected = await readFile("test/expected/wgsl-legal.min.js", "utf8");
+
+		t.is(actual.replace(EOL, ""), expected.replace(EOL, ""));
+
+	});
+
+});