split emoji support methods from the async module

3 files changed, 297 insertions, 0 deletions

diff --git a/app/assets/javascripts/emoji/support/index.js b/app/assets/javascripts/emoji/support/index.js
new file mode 100644
index 00000000000..1f7852dd487
--- /dev/null
+++ b/app/assets/javascripts/emoji/support/index.js
@@ -0,0 +1,10 @@
+import isEmojiUnicodeSupported from './is_emoji_unicode_supported';
+import getUnicodeSupportMap from './unicode_support_map';
+
+// cache browser support map between calls
+let browserUnicodeSupportMap;
+
+export default function isEmojiUnicodeSupportedByBrowser(emojiUnicode, unicodeVersion) {
+  browserUnicodeSupportMap = browserUnicodeSupportMap || getUnicodeSupportMap();
+  return isEmojiUnicodeSupported(browserUnicodeSupportMap, emojiUnicode, unicodeVersion);
+}
diff --git a/app/assets/javascripts/emoji/support/is_emoji_unicode_supported.js b/app/assets/javascripts/emoji/support/is_emoji_unicode_supported.js
new file mode 100644
index 00000000000..3fd23efa9f8
--- /dev/null
+++ b/app/assets/javascripts/emoji/support/is_emoji_unicode_supported.js
@@ -0,0 +1,120 @@
+// On Windows, flags render as two-letter country codes, see http://emojipedia.org/flags/
+const flagACodePoint = 127462; // parseInt('1F1E6', 16)
+const flagZCodePoint = 127487; // parseInt('1F1FF', 16)
+function isFlagEmoji(emojiUnicode) {
+  const cp = emojiUnicode.codePointAt(0);
+  // Length 4 because flags are made of 2 characters which are surrogate pairs
+  return emojiUnicode.length === 4 && cp >= flagACodePoint && cp <= flagZCodePoint;
+}
+
+// Chrome <57 renders keycaps oddly
+// See https://bugs.chromium.org/p/chromium/issues/detail?id=632294
+// Same issue on Windows also fixed in Chrome 57, http://i.imgur.com/rQF7woO.png
+function isKeycapEmoji(emojiUnicode) {
+  return emojiUnicode.length === 3 && emojiUnicode[2] === '\u20E3';
+}
+
+// Check for a skin tone variation emoji which aren't always supported
+const tone1 = 127995;// parseInt('1F3FB', 16)
+const tone5 = 127999;// parseInt('1F3FF', 16)
+function isSkinToneComboEmoji(emojiUnicode) {
+  return emojiUnicode.length > 2 && Array.from(emojiUnicode).some((char) => {
+    const cp = char.codePointAt(0);
+    return cp >= tone1 && cp <= tone5;
+  });
+}
+
+// macOS supports most skin tone emoji's but
+// doesn't support the skin tone versions of horse racing
+const horseRacingCodePoint = 127943;// parseInt('1F3C7', 16)
+function isHorceRacingSkinToneComboEmoji(emojiUnicode) {
+  const firstCharacter = Array.from(emojiUnicode)[0];
+  return firstCharacter && firstCharacter.codePointAt(0) === horseRacingCodePoint &&
+    isSkinToneComboEmoji(emojiUnicode);
+}
+
+// Check for `family_*`, `kiss_*`, `couple_*`
+// For ex. Windows 8.1 Firefox 51.0.1, doesn't support these
+const zwj = 8205; // parseInt('200D', 16)
+const personStartCodePoint = 128102; // parseInt('1F466', 16)
+const personEndCodePoint = 128105; // parseInt('1F469', 16)
+function isPersonZwjEmoji(emojiUnicode) {
+  let hasPersonEmoji = false;
+  let hasZwj = false;
+  Array.from(emojiUnicode).forEach((character) => {
+    const cp = character.codePointAt(0);
+    if (cp === zwj) {
+      hasZwj = true;
+    } else if (cp >= personStartCodePoint && cp <= personEndCodePoint) {
+      hasPersonEmoji = true;
+    }
+  });
+
+  return hasPersonEmoji && hasZwj;
+}
+
+// Helper so we don't have to run `isFlagEmoji` twice
+// in `isEmojiUnicodeSupported` logic
+function checkFlagEmojiSupport(unicodeSupportMap, emojiUnicode) {
+  const isFlagResult = isFlagEmoji(emojiUnicode);
+  return (
+    (unicodeSupportMap.flag && isFlagResult) ||
+    !isFlagResult
+  );
+}
+
+// Helper so we don't have to run `isSkinToneComboEmoji` twice
+// in `isEmojiUnicodeSupported` logic
+function checkSkinToneModifierSupport(unicodeSupportMap, emojiUnicode) {
+  const isSkinToneResult = isSkinToneComboEmoji(emojiUnicode);
+  return (
+    (unicodeSupportMap.skinToneModifier && isSkinToneResult) ||
+    !isSkinToneResult
+  );
+}
+
+// Helper func so we don't have to run `isHorceRacingSkinToneComboEmoji` twice
+// in `isEmojiUnicodeSupported` logic
+function checkHorseRacingSkinToneComboEmojiSupport(unicodeSupportMap, emojiUnicode) {
+  const isHorseRacingSkinToneResult = isHorceRacingSkinToneComboEmoji(emojiUnicode);
+  return (
+    (unicodeSupportMap.horseRacing && isHorseRacingSkinToneResult) ||
+    !isHorseRacingSkinToneResult
+  );
+}
+
+// Helper so we don't have to run `isPersonZwjEmoji` twice
+// in `isEmojiUnicodeSupported` logic
+function checkPersonEmojiSupport(unicodeSupportMap, emojiUnicode) {
+  const isPersonZwjResult = isPersonZwjEmoji(emojiUnicode);
+  return (
+    (unicodeSupportMap.personZwj && isPersonZwjResult) ||
+    !isPersonZwjResult
+  );
+}
+
+// Takes in a support map and determines whether
+// the given unicode emoji is supported on the platform.
+//
+// Combines all the edge case tests into a one-stop shop method
+function isEmojiUnicodeSupported(unicodeSupportMap = {}, emojiUnicode, unicodeVersion) {
+  const isOlderThanChrome57 = unicodeSupportMap.meta && unicodeSupportMap.meta.isChrome &&
+    unicodeSupportMap.meta.chromeVersion < 57;
+
+  // For comments about each scenario, see the comments above each individual respective function
+  return unicodeSupportMap[unicodeVersion] &&
+    !(isOlderThanChrome57 && isKeycapEmoji(emojiUnicode)) &&
+    checkFlagEmojiSupport(unicodeSupportMap, emojiUnicode) &&
+    checkSkinToneModifierSupport(unicodeSupportMap, emojiUnicode) &&
+    checkHorseRacingSkinToneComboEmojiSupport(unicodeSupportMap, emojiUnicode) &&
+    checkPersonEmojiSupport(unicodeSupportMap, emojiUnicode);
+}
+
+export {
+  isEmojiUnicodeSupported as default,
+  isFlagEmoji,
+  isKeycapEmoji,
+  isSkinToneComboEmoji,
+  isHorceRacingSkinToneComboEmoji,
+  isPersonZwjEmoji,
+};
diff --git a/app/assets/javascripts/emoji/support/unicode_support_map.js b/app/assets/javascripts/emoji/support/unicode_support_map.js
new file mode 100644
index 00000000000..755381c2f95
--- /dev/null
+++ b/app/assets/javascripts/emoji/support/unicode_support_map.js
@@ -0,0 +1,167 @@
+import AccessorUtilities from '../../lib/utils/accessor';
+
+const unicodeSupportTestMap = {
+  // man, student (emojione does not have any of these yet), http://emojipedia.org/emoji-zwj-sequences/
+  // occupationZwj: '\u{1F468}\u{200D}\u{1F393}',
+  // woman, biking (emojione does not have any of these yet), http://emojipedia.org/emoji-zwj-sequences/
+  // sexZwj: '\u{1F6B4}\u{200D}\u{2640}',
+  // family_mwgb
+  // Windows 8.1, Firefox 51.0.1 does not support `family_`, `kiss_`, `couple_`
+  personZwj: '\u{1F468}\u{200D}\u{1F469}\u{200D}\u{1F467}\u{200D}\u{1F466}',
+  // horse_racing_tone5
+  // Special case that is not supported on macOS 10.12 even though `skinToneModifier` succeeds
+  horseRacing: '\u{1F3C7}\u{1F3FF}',
+  // US flag, http://emojipedia.org/flags/
+  flag: '\u{1F1FA}\u{1F1F8}',
+  // http://emojipedia.org/modifiers/
+  skinToneModifier: [
+    // spy_tone5
+    '\u{1F575}\u{1F3FF}',
+    // person_with_ball_tone5
+    '\u{26F9}\u{1F3FF}',
+    // angel_tone5
+    '\u{1F47C}\u{1F3FF}',
+  ],
+  // rofl, http://emojipedia.org/unicode-9.0/
+  '9.0': '\u{1F923}',
+  // metal, http://emojipedia.org/unicode-8.0/
+  '8.0': '\u{1F918}',
+  // spy, http://emojipedia.org/unicode-7.0/
+  '7.0': '\u{1F575}',
+  // expressionless, http://emojipedia.org/unicode-6.1/
+  6.1: '\u{1F611}',
+  // japanese_goblin, http://emojipedia.org/unicode-6.0/
+  '6.0': '\u{1F47A}',
+  // sailboat, http://emojipedia.org/unicode-5.2/
+  5.2: '\u{26F5}',
+  // mahjong, http://emojipedia.org/unicode-5.1/
+  5.1: '\u{1F004}',
+  // gear, http://emojipedia.org/unicode-4.1/
+  4.1: '\u{2699}',
+  // zap, http://emojipedia.org/unicode-4.0/
+  '4.0': '\u{26A1}',
+  // recycle, http://emojipedia.org/unicode-3.2/
+  3.2: '\u{267B}',
+  // information_source, http://emojipedia.org/unicode-3.0/
+  '3.0': '\u{2139}',
+  // heart, http://emojipedia.org/unicode-1.1/
+  1.1: '\u{2764}',
+};
+
+function checkPixelInImageDataArray(pixelOffset, imageDataArray) {
+  // `4 *` because RGBA
+  const indexOffset = 4 * pixelOffset;
+  const hasColor = imageDataArray[indexOffset + 0] ||
+    imageDataArray[indexOffset + 1] ||
+    imageDataArray[indexOffset + 2];
+  const isVisible = imageDataArray[indexOffset + 3];
+  // Check for some sort of color other than black
+  if (hasColor && isVisible) {
+    return true;
+  }
+  return false;
+}
+
+const chromeMatches = navigator.userAgent.match(/Chrom(?:e|ium)\/([0-9]+)\./);
+const isChrome = chromeMatches && chromeMatches.length > 0;
+const chromeVersion = chromeMatches && chromeMatches[1] && parseInt(chromeMatches[1], 10);
+
+// We use 16px because mobile Safari (iOS 9.3) doesn't properly scale emojis :/
+// See 32px, https://i.imgur.com/htY6Zym.png
+// See 16px, https://i.imgur.com/FPPsIF8.png
+const fontSize = 16;
+function generateUnicodeSupportMap(testMap) {
+  const testMapKeys = Object.keys(testMap);
+  const numTestEntries = testMapKeys
+    .reduce((list, testKey) => list.concat(testMap[testKey]), []).length;
+
+  const canvas = document.createElement('canvas');
+  (window.gl || window).testEmojiUnicodeSupportMapCanvas = canvas;
+  const ctx = canvas.getContext('2d');
+  canvas.width = (2 * fontSize);
+  canvas.height = (numTestEntries * fontSize);
+  ctx.fillStyle = '#000000';
+  ctx.textBaseline = 'middle';
+  ctx.font = `${fontSize}px "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol"`;
+  // Write each emoji to the canvas vertically
+  let writeIndex = 0;
+  testMapKeys.forEach((testKey) => {
+    const testEntry = testMap[testKey];
+    [].concat(testEntry).forEach((emojiUnicode) => {
+      ctx.fillText(emojiUnicode, 0, (writeIndex * fontSize) + (fontSize / 2));
+      writeIndex += 1;
+    });
+  });
+
+  // Read from the canvas
+  const resultMap = {};
+  let readIndex = 0;
+  testMapKeys.forEach((testKey) => {
+    const testEntry = testMap[testKey];
+    // This needs to be a `reduce` instead of `every` because we need to
+    // keep the `readIndex` in sync from the writes by running all entries
+    const isTestSatisfied = [].concat(testEntry).reduce((isSatisfied) => {
+      // Sample along the vertical-middle for a couple of characters
+      const imageData = ctx.getImageData(
+          0,
+          (readIndex * fontSize) + (fontSize / 2),
+          2 * fontSize,
+          1,
+        ).data;
+
+      let isValidEmoji = false;
+      for (let currentPixel = 0; currentPixel < 64; currentPixel += 1) {
+        const isLookingAtFirstChar = currentPixel < fontSize;
+        const isLookingAtSecondChar = currentPixel >= (fontSize + (fontSize / 2));
+        // Check for the emoji somewhere along the row
+        if (isLookingAtFirstChar && checkPixelInImageDataArray(currentPixel, imageData)) {
+          isValidEmoji = true;
+
+        // Check to see that nothing is rendered next to the first character
+        // to ensure that the ZWJ sequence rendered as one piece
+        } else if (isLookingAtSecondChar && checkPixelInImageDataArray(currentPixel, imageData)) {
+          isValidEmoji = false;
+          break;
+        }
+      }
+
+      readIndex += 1;
+      return isSatisfied && isValidEmoji;
+    }, true);
+
+    resultMap[testKey] = isTestSatisfied;
+  });
+
+  resultMap.meta = {
+    isChrome,
+    chromeVersion,
+  };
+
+  return resultMap;
+}
+
+export default function getUnicodeSupportMap() {
+  let unicodeSupportMap;
+  let userAgentFromCache;
+
+  const isLocalStorageAvailable = AccessorUtilities.isLocalStorageAccessSafe();
+
+  if (isLocalStorageAvailable) userAgentFromCache = window.localStorage.getItem('gl-emoji-user-agent');
+
+  try {
+    unicodeSupportMap = JSON.parse(window.localStorage.getItem('gl-emoji-unicode-support-map'));
+  } catch (err) {
+    // swallow
+  }
+
+  if (!unicodeSupportMap || userAgentFromCache !== navigator.userAgent) {
+    unicodeSupportMap = generateUnicodeSupportMap(unicodeSupportTestMap);
+
+    if (isLocalStorageAvailable) {
+      window.localStorage.setItem('gl-emoji-user-agent', navigator.userAgent);
+      window.localStorage.setItem('gl-emoji-unicode-support-map', JSON.stringify(unicodeSupportMap));
+    }
+  }
+
+  return unicodeSupportMap;
+}