chore: Add text_utils.js (#4941)

shaka-project · Jan 30, 2023 · ff80ae6 · ff80ae6
1 parent 056588b
commit ff80ae6
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Showing 4 changed files with 93 additions and 128 deletions.
diff --git a/build/types/core b/build/types/core
@@ -56,6 +56,7 @@
 +../../lib/text/cue.js
 +../../lib/text/simple_text_displayer.js
 +../../lib/text/text_engine.js
++../../lib/text/text_utils.js
 +../../lib/text/ui_text_displayer.js
 +../../lib/text/web_vtt_generator.js
 

diff --git a/lib/text/simple_text_displayer.js b/lib/text/simple_text_displayer.js
@@ -14,6 +14,7 @@ goog.provide('shaka.text.SimpleTextDisplayer');
 goog.require('goog.asserts');
 goog.require('shaka.log');
 goog.require('shaka.text.Cue');
+goog.require('shaka.text.Utils');
 
 
 /**
@@ -79,70 +80,7 @@ shaka.text.SimpleTextDisplayer = class {
    * @export
    */
   append(cues) {
-    // Flatten nested cue payloads recursively.  If a cue has nested cues,
-    // their contents should be combined and replace the payload of the parent.
-    const flattenPayload = (cue) => {
-      // Handle styles (currently bold/italics/underline).
-      // TODO add support for color rendering.
-      const openStyleTags = [];
-      const bold = cue.fontWeight >= shaka.text.Cue.fontWeight.BOLD;
-      const italics = cue.fontStyle == shaka.text.Cue.fontStyle.ITALIC;
-      const underline = cue.textDecoration.includes(
-          shaka.text.Cue.textDecoration.UNDERLINE);
-      if (bold) {
-        openStyleTags.push('b');
-      }
-      if (italics) {
-        openStyleTags.push('i');
-      }
-      if (underline) {
-        openStyleTags.push('u');
-      }
-
-      // Prefix opens tags, suffix closes tags in reverse order of opening.
-      const prefixStyleTags = openStyleTags.reduce((acc, tag) => {
-        return `${acc}<${tag}>`;
-      }, '');
-      const suffixStyleTags = openStyleTags.reduceRight((acc, tag) => {
-        return `${acc}</${tag}>`;
-      }, '');
-
-      if (cue.lineBreak) {
-        // This is a vertical lineBreak, so insert a newline.
-        return '\n';
-      } else if (cue.nestedCues.length) {
-        return cue.nestedCues.map(flattenPayload).join('');
-      } else {
-        // This is a real cue.
-        return prefixStyleTags + cue.payload + suffixStyleTags;
-      }
-    };
-
-    // We don't want to modify the array or objects passed in, since we don't
-    // technically own them.  So we build a new array and replace certain items
-    // in it if they need to be flattened.
-    // We also don't want to flatten the text payloads starting at a container
-    // element; otherwise, for containers encapsulating multiple caption lines,
-    // the lines would merge into a single cue. This is undesirable when a
-    // subset of the captions are outside of the append time window. To fix
-    // this, we only call flattenPayload() starting at elements marked as
-    // isContainer = false.
-    const getCuesToFlatten = (cues, result) => {
-      for (const cue of cues) {
-        if (cue.isContainer) {
-          // Recurse to find the actual text payload cues.
-          getCuesToFlatten(cue.nestedCues, result);
-        } else {
-          // Flatten the payload.
-          const flatCue = cue.clone();
-          flatCue.nestedCues = [];
-          flatCue.payload = flattenPayload(cue);
-          result.push(flatCue);
-        }
-      }
-      return result;
-    };
-    const flattenedCues = getCuesToFlatten(cues, []);
+    const flattenedCues = shaka.text.Utils.getCuesToFlatten(cues, []);
 
     // Convert cues.
     const textTrackCues = [];

diff --git a/lib/text/text_utils.js b/lib/text/text_utils.js
@@ -0,0 +1,88 @@
+/*! @license
+ * Shaka Player
+ * Copyright 2016 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+goog.provide('shaka.text.Utils');
+
+goog.require('shaka.text.Cue');
+
+
+shaka.text.Utils = class {
+  /**
+   * Flatten nested cue payloads recursively.  If a cue has nested cues,
+   * their contents should be combined and replace the payload of the parent.
+   *
+   * @param {!shaka.text.Cue} cue
+   * @return {string}
+   * @private
+   */
+  static flattenPayload_(cue) {
+    // Handle styles (currently bold/italics/underline).
+    // TODO: add support for color rendering.
+    const openStyleTags = [];
+    const bold = cue.fontWeight >= shaka.text.Cue.fontWeight.BOLD;
+    const italics = cue.fontStyle == shaka.text.Cue.fontStyle.ITALIC;
+    const underline = cue.textDecoration.includes(
+        shaka.text.Cue.textDecoration.UNDERLINE);
+    if (bold) {
+      openStyleTags.push('b');
+    }
+    if (italics) {
+      openStyleTags.push('i');
+    }
+    if (underline) {
+      openStyleTags.push('u');
+    }
+
+    // Prefix opens tags, suffix closes tags in reverse order of opening.
+    const prefixStyleTags = openStyleTags.reduce((acc, tag) => {
+      return `${acc}<${tag}>`;
+    }, '');
+    const suffixStyleTags = openStyleTags.reduceRight((acc, tag) => {
+      return `${acc}</${tag}>`;
+    }, '');
+
+    if (cue.lineBreak) {
+      // This is a vertical lineBreak, so insert a newline.
+      return '\n';
+    } else if (cue.nestedCues.length) {
+      return cue.nestedCues.map(shaka.text.Utils.flattenPayload_).join('');
+    } else {
+      // This is a real cue.
+      return prefixStyleTags + cue.payload + suffixStyleTags;
+    }
+  }
+
+  /**
+   * We don't want to modify the array or objects passed in, since we don't
+   * technically own them.  So we build a new array and replace certain items
+   * in it if they need to be flattened.
+   * We also don't want to flatten the text payloads starting at a container
+   * element; otherwise, for containers encapsulating multiple caption lines,
+   * the lines would merge into a single cue. This is undesirable when a
+   * subset of the captions are outside of the append time window. To fix
+   * this, we only call flattenPayload() starting at elements marked as
+   * isContainer = false.
+   *
+   * @param {!Array.<!shaka.text.Cue>} cues
+   * @param {!Array.<!shaka.text.Cue>} result
+   * @return {!Array.<!shaka.text.Cue>}
+   */
+  static getCuesToFlatten(cues, result) {
+    for (const cue of cues) {
+      if (cue.isContainer) {
+        // Recurse to find the actual text payload cues.
+        shaka.text.Utils.getCuesToFlatten(cue.nestedCues, result);
+      } else {
+        // Flatten the payload.
+        const flatCue = cue.clone();
+        flatCue.nestedCues = [];
+        flatCue.payload = shaka.text.Utils.flattenPayload_(cue);
+        result.push(flatCue);
+      }
+    }
+    return result;
+  }
+};
diff --git a/lib/text/web_vtt_generator.js b/lib/text/web_vtt_generator.js
@@ -7,6 +7,7 @@
 goog.provide('shaka.text.WebVttGenerator');
 
 goog.require('shaka.text.Cue');
+goog.require('shaka.text.Utils');
 
 
 /**
@@ -20,45 +21,6 @@ shaka.text.WebVttGenerator = class {
    * @return {string}
    */
   static convert(cues, adCuePoints) {
-    // Flatten nested cue payloads recursively.  If a cue has nested cues,
-    // their contents should be combined and replace the payload of the parent.
-    const flattenPayload = (cue) => {
-      // Handle styles (currently bold/italics/underline).
-      // TODO: add support for color rendering.
-      const openStyleTags = [];
-      const bold = cue.fontWeight >= shaka.text.Cue.fontWeight.BOLD;
-      const italics = cue.fontStyle == shaka.text.Cue.fontStyle.ITALIC;
-      const underline = cue.textDecoration.includes(
-          shaka.text.Cue.textDecoration.UNDERLINE);
-      if (bold) {
-        openStyleTags.push('b');
-      }
-      if (italics) {
-        openStyleTags.push('i');
-      }
-      if (underline) {
-        openStyleTags.push('u');
-      }
-
-      // Prefix opens tags, suffix closes tags in reverse order of opening.
-      const prefixStyleTags = openStyleTags.reduce((acc, tag) => {
-        return `${acc}<${tag}>`;
-      }, '');
-      const suffixStyleTags = openStyleTags.reduceRight((acc, tag) => {
-        return `${acc}</${tag}>`;
-      }, '');
-
-      if (cue.lineBreak) {
-        // This is a vertical lineBreak, so insert a newline.
-        return '\n';
-      } else if (cue.nestedCues.length) {
-        return cue.nestedCues.map(flattenPayload).join('');
-      } else {
-        // This is a real cue.
-        return prefixStyleTags + cue.payload + suffixStyleTags;
-      }
-    };
-
     const webvttTimeString = (time) => {
       let newTime = time;
       for (const adCuePoint of adCuePoints) {
@@ -78,31 +40,7 @@ shaka.text.WebVttGenerator = class {
           milliseconds;
     };
 
-    // We don't want to modify the array or objects passed in, since we don't
-    // technically own them.  So we build a new array and replace certain items
-    // in it if they need to be flattened.
-    // We also don't want to flatten the text payloads starting at a container
-    // element; otherwise, for containers encapsulating multiple caption lines,
-    // the lines would merge into a single cue. This is undesirable when a
-    // subset of the captions are outside of the append time window. To fix
-    // this, we only call flattenPayload() starting at elements marked as
-    // isContainer = false.
-    const getCuesToFlatten = (cues, result) => {
-      for (const cue of cues) {
-        if (cue.isContainer) {
-          // Recurse to find the actual text payload cues.
-          getCuesToFlatten(cue.nestedCues, result);
-        } else {
-          // Flatten the payload.
-          const flatCue = cue.clone();
-          flatCue.nestedCues = [];
-          flatCue.payload = flattenPayload(cue);
-          result.push(flatCue);
-        }
-      }
-      return result;
-    };
-    const flattenedCues = getCuesToFlatten(cues, []);
+    const flattenedCues = shaka.text.Utils.getCuesToFlatten(cues, []);
 
     let webvttString = 'WEBVTT\n\n';
     for (const cue of flattenedCues) {