Revert "Revert "Revert me: Support shelling out to the hb-subset bina…

…ry instead of using the wasm build""

This reverts commit d545459.

lib/subsetLocalFontWithHarfbuzz.js

@@ -5,6 +5,10 @@ const _ = require('lodash');
 const pathModule = require('path');
 const wawoff2 = require('wawoff2');
 const woffTool = require('woff2sfnt-sfnt2woff');
+const childProcess = require('child_process');
+const getTemporaryFilePath = require('gettemporaryfilepath');
+const { readFile, writeFile, unlink } = require('fs').promises;
+const execFile = require('util').promisify(childProcess.execFile);
 
 const loadAndInitializeHarfbuzz = _.once(async () => {
   const {
@@ -30,56 +34,92 @@ module.exports = async (originalFont, targetFormat, text) => {
     originalFont = await wawoff2.decompress(originalFont);
   }
 
-  const fontBuffer = exports.malloc(originalFont.byteLength);
-  heapu8.set(new Uint8Array(originalFont), fontBuffer);
+  let subsetFont;
+  if (true) {
+    text = text || '*';
 
-  // Create the face
-  const blob = exports.hb_blob_create(
-    fontBuffer,
-    originalFont.byteLength,
-    2, // HB_MEMORY_MODE_WRITABLE
-    0,
-    0
-  );
-  const face = exports.hb_face_create(blob, 0);
-  exports.hb_blob_destroy(blob);
+    const tempInputFileName = getTemporaryFilePath({
+      prefix: 'input-',
+      suffix: `.ttf`,
+    });
+    const tempOutputFileName = getTemporaryFilePath({
+      prefix: 'output-',
+      suffix: `.ttf`,
+    });
 
-  // Add glyph indices and subset
-  const glyphs = exports.hb_set_create();
+    const args = [
+      `--output-file=${tempOutputFileName}`,
+      tempInputFileName,
+      text,
+    ];
 
-  for (let i = 0; i < text.length; i += 1) {
-    exports.hb_set_add(glyphs, text.charCodeAt(i));
-  }
+    try {
+      await writeFile(tempInputFileName, originalFont);
+      await execFile('../harfbuzz/build/util/hb-subset', args);
+      // Await to make sure the output file has been consumed before we delete it in the finally block below:
+      subsetFont = await readFile(tempOutputFileName);
+    } finally {
+      unlink(tempInputFileName).then(
+        () => {},
+        () => {}
+      );
+      unlink(tempOutputFileName).then(
+        () => {},
+        () => {}
+      );
+    }
+  } else {
+    const fontBuffer = exports.malloc(originalFont.byteLength);
+    heapu8.set(new Uint8Array(originalFont), fontBuffer);
 
-  const input = exports.hb_subset_input_create_or_fail();
-  const inputGlyphs = exports.hb_subset_input_unicode_set(input);
-  exports.hb_set_union(inputGlyphs, glyphs);
-  const subset = exports.hb_subset(face, input);
+    // Create the face
+    const blob = exports.hb_blob_create(
+      fontBuffer,
+      originalFont.byteLength,
+      2, // HB_MEMORY_MODE_WRITABLE
+      0,
+      0
+    );
+    const face = exports.hb_face_create(blob, 0);
+    exports.hb_blob_destroy(blob);
 
-  // Clean up
-  exports.hb_subset_input_destroy(input);
+    // Add glyph indices and subset
+    const glyphs = exports.hb_set_create();
 
-  // Get result blob
-  const result = exports.hb_face_reference_blob(subset);
+    for (let i = 0; i < text.length; i += 1) {
+      exports.hb_set_add(glyphs, text.charCodeAt(i));
+    }
 
-  const offset = exports.hb_blob_get_data(result, 0);
-  const subsetFontBlob = heapu8.slice(
-    offset,
-    offset + exports.hb_blob_get_length(result)
-  );
+    const input = exports.hb_subset_input_create_or_fail();
+    const inputGlyphs = exports.hb_subset_input_unicode_set(input);
+    exports.hb_set_union(inputGlyphs, glyphs);
+    const subset = exports.hb_subset(face, input);
 
-  // Clean up
-  exports.hb_blob_destroy(result);
-  exports.hb_face_destroy(subset);
+    // Clean up
+    exports.hb_subset_input_destroy(input);
+
+    // Get result blob
+    const result = exports.hb_face_reference_blob(subset);
+
+    const offset = exports.hb_blob_get_data(result, 0);
+    const subsetFontBlob = heapu8.slice(
+      offset,
+      offset + exports.hb_blob_get_length(result)
+    );
+
+    // Clean up
+    exports.hb_blob_destroy(result);
+    exports.hb_face_destroy(subset);
+    subsetFont = subsetFontBlob;
+  }
 
-  let subsetFont;
   if (targetFormat === 'woff2') {
-    subsetFont = Buffer.from(await wawoff2.compress(subsetFontBlob));
+    subsetFont = Buffer.from(await wawoff2.compress(subsetFont));
   } else if (targetFormat === 'woff') {
-    subsetFont = woffTool.toWoff(subsetFontBlob);
+    subsetFont = woffTool.toWoff(subsetFont);
   } else {
     // targetFormat === 'truetype'
-    subsetFont = Buffer.from(subsetFontBlob);
+    subsetFont = Buffer.from(subsetFont);
   }
   return subsetFont;
 };