feat!: Support streaming contents (#33)

index.js

@@ -1,6 +1,7 @@
 'use strict';
 
 var File = require('vinyl');
+var vinylContents = require('vinyl-contents');
 
 var helpers = require('./lib/helpers');
 
@@ -12,25 +13,28 @@ function add(file, callback) {
     return callback(new Error(PLUGIN_NAME + '-add: Not a vinyl file'));
   }
 
-  // Bail early with an error if file has streaming contents
-  if (file.isStream()) {
-    return callback(new Error(PLUGIN_NAME + '-add: Streaming not supported'));
-  }
-
   // Bail early successfully if file is null or already has a sourcemap
   if (file.isNull() || file.sourceMap) {
     return callback(null, file);
   }
 
-  var state = {
-    path: '', // Root path for the sources in the map
-    map: null,
-    content: file.contents.toString(),
-    // TODO: handle this?
-    preExistingComment: null,
-  };
+  vinylContents(file, onContents);
+
+  function onContents(err, contents) {
+    if (err) {
+      return callback(err);
+    }
+
+    var state = {
+      path: '', // Root path for the sources in the map
+      map: null,
+      content: contents.toString(),
+      // TODO: handle this?
+      preExistingComment: null,
+    };
 
-  helpers.addSourceMaps(file, state, callback);
+    helpers.addSourceMaps(file, state, callback);
+  }
 }
 
 function write(file, destPath, callback) {
@@ -45,11 +49,6 @@ function write(file, destPath, callback) {
     return callback(new Error(PLUGIN_NAME + '-write: Not a vinyl file'));
   }
 
-  // Bail early with an error if file has streaming contents
-  if (file.isStream()) {
-    return callback(new Error(PLUGIN_NAME + '-write: Streaming not supported'));
-  }
-
   // Bail early successfully if file is null or doesn't have sourcemap
   if (file.isNull() || !file.sourceMap) {
     return callback(null, file);

lib/helpers.js

@@ -5,14 +5,17 @@ var os = require('os');
 var TextDecoder = require('util').TextDecoder;
 
 var fs = require('graceful-fs');
+var Readable = require('streamx').Readable;
+var Transform = require('streamx').Transform;
 var nal = require('now-and-later');
 var File = require('vinyl');
 var convert = require('convert-source-map');
 
 var urlRegex = /^(https?|webpack(-[^:]+)?):\/\//;
 
-var bufCR = Buffer.from('\r\n');
-var bufNL = Buffer.from('\n');
+var bufCR = Buffer.from('\r');
+var bufCRLF = Buffer.from('\r\n');
+var bufLF = Buffer.from('\n');
 var bufEOL = Buffer.from(os.EOL);
 
 var decoder = new TextDecoder('utf-8', { ignoreBOM: false });
@@ -39,7 +42,11 @@ function loadSourceMap(file, state, callback) {
     state.path = file.dirname;
     state.content = convert.removeComments(state.content);
     // Remove source map comment from source
-    file.contents = Buffer.from(state.content, 'utf8');
+    if (file.isStream()) {
+      file.contents = Readable.from(state.content);
+    } else {
+      file.contents = Buffer.from(state.content, 'utf8');
+    }
     return callback();
   }
 
@@ -51,7 +58,11 @@ function loadSourceMap(file, state, callback) {
     mapFile = path.resolve(file.dirname, mapComment[1] || mapComment[2]);
     state.content = convert.removeMapFileComments(state.content);
     // Remove source map comment from source
-    file.contents = Buffer.from(state.content, 'utf8');
+    if (file.isStream()) {
+      file.contents = Readable.from(state.content);
+    } else {
+      file.contents = Buffer.from(state.content, 'utf8');
+    }
   } else {
     // If no comment try map file with same name as source file
     mapFile = file.path + '.map';
@@ -232,23 +243,100 @@ function writeSourceMaps(file, destPath, callback) {
   }
 
   // Append source map comment
-  file.contents = appendBuffer(file.contents, Buffer.from(comment));
+  file = append(file, Buffer.from(comment));
 
   callback(null, file, sourceMapFile);
 }
 
+function append(file, comment) {
+  if (file.isBuffer()) {
+    file.contents = appendBuffer(file.contents, comment);
+  }
+
+  if (file.isStream()) {
+    file.contents = file.contents.pipe(appendStream(comment));
+  }
+
+  return file;
+}
+
 function appendBuffer(buf1, buf2) {
   var eol;
-  if (buf1.slice(-2).equals(bufCR)) {
+  if (buf1.slice(-2).equals(bufCRLF)) {
+    eol = bufCRLF;
+  } else if (buf1.slice(-1).equals(bufLF)) {
+    eol = bufLF;
+  } else if (buf1.slice(-1).equals(bufCR)) {
     eol = bufCR;
-  } else if (buf1.slice(-1).equals(bufNL)) {
-    eol = bufNL;
   } else {
     eol = bufEOL;
   }
   return Buffer.concat([buf1, buf2, eol]);
 }
 
+// Implementation heavily inspired by https://github.com/maxogden/eol-stream
+function appendStream(comment) {
+  var crAtEnd = false;
+  var eol = bufEOL;
+
+  return new Transform({
+    transform: detect,
+    flush: flush,
+  });
+
+  function detect(chunk, callback) {
+    var isString = typeof chunk === 'string';
+
+    var cr = isString ? bufCR.toString() : bufCR[0];
+    var lf = isString ? bufLF.toString() : bufLF[0];
+
+    if (crAtEnd) {
+      if (chunk[0] === lf) {
+        eol = bufCRLF;
+      } else {
+        eol = bufCR;
+      }
+      // Reset the flag because we search for the _last_ line ending
+      crAtEnd = false;
+      return callback(null, chunk);
+    }
+
+    var i = 0;
+    while (i < chunk.length) {
+      if (chunk[i] === cr) {
+        if (i === chunk.length - 1) {
+          // Need to read the next chunk to see if it is a CRLF
+          crAtEnd = true;
+          i += 1;
+        } else if (chunk[i + 1] === lf) {
+          eol = bufCRLF;
+          // We skip two because we saw the CRLF
+          i += 2;
+        } else {
+          eol = bufCR;
+          i += 1;
+        }
+        continue;
+      }
+
+      if (chunk[i] === lf) {
+        eol = bufLF;
+      }
+
+      i += 1;
+    }
+
+    callback(null, chunk);
+  }
+
+  function flush(cb) {
+    this.push(comment);
+    this.push(eol);
+
+    cb();
+  }
+}
+
 function normalizeRelpath(fp) {
   // Since we only ever operate on relative paths,
   // this utility shouldn't need to handle path roots

package.json

@@ -27,7 +27,9 @@
     "convert-source-map": "^1.8.0",
     "graceful-fs": "^4.2.10",
     "now-and-later": "^3.0.0",
-    "vinyl": "^3.0.0"
+    "streamx": "^2.12.5",
+    "vinyl": "^3.0.0",
+    "vinyl-contents": "^2.0.0"
   },
   "devDependencies": {
     "eslint": "^7.32.0",
@@ -36,7 +38,7 @@
     "expect": "^27.5.1",
     "mocha": "^8.4.0",
     "nyc": "^15.1.0",
-    "streamx": "^2.12.5"
+    "readable-stream": "^3.6.0"
   },
   "nyc": {
     "extension": [