added doiuse plugin for postcss

3 files changed, 190 insertions, 0 deletions

diff --git a/node_modules/doiuse/lib/stream/CssUsageDuplex.js b/node_modules/doiuse/lib/stream/CssUsageDuplex.js
new file mode 100644
index 00000000..063ed1dc
--- /dev/null
+++ b/node_modules/doiuse/lib/stream/CssUsageDuplex.js
@@ -0,0 +1,36 @@
+/* eslint-disable no-underscore-dangle */
+
+import { pipeline } from 'node:stream';
+
+import Tokenize from 'css-tokenize';
+import Duplexify from 'duplexify';
+
+import RuleUsageTransform from './RuleUsageTransform.js';
+import SourceMapTransform from './SourceMapTransform.js';
+
+/** @typedef {import('../../data/features.js').FeatureKeys} FeatureKeys */
+
+export default class CssUsageDuplex extends Duplexify {
+  /**
+   * @param {Object} options
+   * @param {string} options.browsers
+   * @param {FeatureKeys[]} [options.ignore]
+   * @param {boolean} [options.skipErrors]
+   * @param {string} [filename] Filename for outputting source code locations.
+   */
+  constructor(options, filename) {
+    const streams = [
+      new Tokenize(),
+      new SourceMapTransform(),
+      new RuleUsageTransform(options, filename),
+    ];
+    pipeline(
+      // @ts-expect-error Bad typings
+      ...streams,
+      () => {
+        // noop (Error handled by Duplexify)
+      },
+    );
+    super(streams[0], streams.at(-1), { objectMode: true });
+  }
+}
diff --git a/node_modules/doiuse/lib/stream/RuleUsageTransform.js b/node_modules/doiuse/lib/stream/RuleUsageTransform.js
new file mode 100644
index 00000000..a2a79d4d
--- /dev/null
+++ b/node_modules/doiuse/lib/stream/RuleUsageTransform.js
@@ -0,0 +1,80 @@
+/* eslint-disable no-underscore-dangle */
+import { Transform } from 'node:stream';
+
+import postcss from 'postcss';
+import sourcemap from 'source-map';
+
+import DoIUse from '../DoIUse.js';
+
+/** @typedef {import('../../data/features.js').FeatureKeys} FeatureKeys */
+/** @typedef {import('./SourceMapTransform.js').SourceMapTransformation} SourceMapTransformation */
+
+export default class RuleUsageTransform extends Transform {
+  /** @type {import("postcss").Processor} */
+  #processor;
+
+  #skipErrors;
+
+  #filename;
+
+  /**
+   * @param {Object} options
+   * @param {string} options.browsers
+   * @param {FeatureKeys[]} [options.ignore]
+   * @param {boolean} [options.skipErrors]
+   * @param {string} [filename]  Filename for outputting source code locations.
+   */
+  constructor(options, filename = '<streaming css input>') {
+    super({
+      objectMode: true,
+    });
+    this.#processor = postcss([new DoIUse({
+      browsers: options.browsers,
+      ignore: options.ignore,
+      onFeatureUsage: (usage) => {
+        this.push(usage);
+      },
+    })]);
+    this.#filename = filename;
+    this.#skipErrors = options.skipErrors;
+  }
+
+  /**
+   * @param {SourceMapTransformation} rule
+   * @param {any} encoding
+   * @param {Function} callback
+   */
+  async _transform(rule, encoding, callback) {
+    let caughtError;
+    try {
+      const mapper = new sourcemap.SourceMapGenerator();
+      const lines = rule.content.split('\n');
+      let oline = rule.line;
+      let ocol = rule.column;
+      for (const [lineNumber, content] of lines.entries()) {
+        mapper.addMapping({
+          generated: { line: lineNumber + 1, column: 1 },
+          original: { line: oline, column: ocol },
+          source: this.#filename,
+        });
+        mapper.addMapping({
+          generated: { line: lineNumber + 1, column: content.length },
+          original: { line: oline, column: ocol + content.length },
+          source: this.#filename,
+        });
+        oline += 1;
+        ocol = 1;
+      }
+      await this.#processor.process(rule.content, {
+        from: this.#filename, map: { prev: mapper.toString() },
+      });
+    } catch (error) {
+      if (this.#skipErrors) {
+        this.emit('warning', error);
+      } else {
+        caughtError = error;
+      }
+    }
+    callback(caughtError);
+  }
+}
diff --git a/node_modules/doiuse/lib/stream/SourceMapTransform.js b/node_modules/doiuse/lib/stream/SourceMapTransform.js
new file mode 100644
index 00000000..6295b1d3
--- /dev/null
+++ b/node_modules/doiuse/lib/stream/SourceMapTransform.js
@@ -0,0 +1,74 @@
+/* eslint-disable no-underscore-dangle */
+import { Transform } from 'node:stream';
+
+const NEW_LINE_CHAR = '\n'.codePointAt(0);
+
+/**
+ * @typedef {Object} SourceMapTransformation
+ * @prop {number} line
+ * @prop {number} column
+ * @prop {string} content
+ */
+
+export default class SourceMapTransform extends Transform {
+  constructor() {
+    super({ objectMode: true });
+  }
+
+  /**
+   * @type {?{location:[number,number], buffers: Buffer[]}}
+   * buffer for the current incoming rule.
+   */
+  #current = null;
+
+  /** track depth to handle rules nested in at-rules. */
+  #depth = 0;
+
+  /** track this and pass it downstream for source mapping. */
+  #line = 1;
+
+  /** track this and pass it downstream for source mapping. */
+  #column = 1;
+
+  /**
+   * @param {[string,Buffer]} chunk
+   * @param {any} encoding
+   * @param {Function} callback
+   */
+  _transform([type, buf], encoding, callback) {
+    if ((type === 'rule_start' || type === 'atrule_start')) {
+      this.#depth += 1;
+    }
+    if (this.#depth > 0 && !this.#current) {
+      this.#current = { location: [this.#line, this.#column], buffers: [] };
+    }
+    if (type === 'rule_end' || type === 'atrule_end') {
+      this.#depth -= 1;
+    }
+
+    if (this.#current) {
+      this.#current.buffers.push(buf);
+      if (this.#depth === 0) {
+        // Push rule
+        this.push({
+          line: this.#current.location[0],
+          column: this.#current.location[1],
+          content: Buffer.concat(this.#current.buffers).toString(),
+        });
+        this.#current = null;
+      }
+    }
+
+    // Update position
+    for (const char of buf) {
+      if (char === NEW_LINE_CHAR) {
+        this.#line += 1;
+        this.#column = 1;
+      } else {
+        this.#column += 1;
+      }
+    }
+
+    callback();
+  }
+}