Create simplified source map class

5 files changed, 143 insertions, 52 deletions

diff --git a/ext/bg/background.html b/ext/bg/background.html
index f7cf6e55..e456717e 100644
--- a/ext/bg/background.html
+++ b/ext/bg/background.html
@@ -38,6 +38,7 @@
         <script src="/bg/js/options.js"></script>
         <script src="/bg/js/profile-conditions.js"></script>
         <script src="/bg/js/request.js"></script>
+        <script src="/bg/js/text-source-map.js"></script>
         <script src="/bg/js/translator.js"></script>
         <script src="/bg/js/util.js"></script>
         <script src="/mixed/js/audio-system.js"></script>
diff --git a/ext/bg/js/japanese.js b/ext/bg/js/japanese.js
index c5873cf1..2a2b39fd 100644
--- a/ext/bg/js/japanese.js
+++ b/ext/bg/js/japanese.js
@@ -158,9 +158,8 @@
         return result;
     }
 
-    function convertHalfWidthKanaToFullWidth(text, sourceMapping) {
+    function convertHalfWidthKanaToFullWidth(text, sourceMap=null) {
         let result = '';
-        const hasSourceMapping = Array.isArray(sourceMapping);
 
         // This function is safe to use charCodeAt instead of codePointAt, since all
         // the relevant characters are represented with a single UTF-16 character code.
@@ -192,10 +191,8 @@
                 }
             }
 
-            if (hasSourceMapping && index > 0) {
-                index = result.length;
-                const v = sourceMapping.splice(index + 1, 1)[0];
-                sourceMapping[index] += v;
+            if (sourceMap !== null && index > 0) {
+                sourceMap.combine(result.length, 1);
             }
             result += c2;
         }
@@ -203,7 +200,7 @@
         return result;
     }
 
-    function convertAlphabeticToKana(text, sourceMapping) {
+    function convertAlphabeticToKana(text, sourceMap=null) {
         let part = '';
         let result = '';
 
@@ -222,7 +219,7 @@
                 c = 0x2d; // '-'
             } else {
                 if (part.length > 0) {
-                    result += convertAlphabeticPartToKana(part, sourceMapping, result.length);
+                    result += convertAlphabeticPartToKana(part, sourceMap, result.length);
                     part = '';
                 }
                 result += char;
@@ -232,17 +229,16 @@
         }
 
         if (part.length > 0) {
-            result += convertAlphabeticPartToKana(part, sourceMapping, result.length);
+            result += convertAlphabeticPartToKana(part, sourceMap, result.length);
         }
         return result;
     }
 
-    function convertAlphabeticPartToKana(text, sourceMapping, sourceMappingStart) {
+    function convertAlphabeticPartToKana(text, sourceMap, sourceMapStart) {
         const result = wanakana.toHiragana(text);
 
         // Generate source mapping
-        if (Array.isArray(sourceMapping)) {
-            if (typeof sourceMappingStart !== 'number') { sourceMappingStart = 0; }
+        if (sourceMap !== null) {
             let i = 0;
             let resultPos = 0;
             const ii = text.length;
@@ -262,18 +258,15 @@
                 // Merge characters
                 const removals = iNext - i - 1;
                 if (removals > 0) {
-                    let sum = 0;
-                    const vs = sourceMapping.splice(sourceMappingStart + 1, removals);
-                    for (const v of vs) { sum += v; }
-                    sourceMapping[sourceMappingStart] += sum;
+                    sourceMap.combine(sourceMapStart, removals);
                 }
-                ++sourceMappingStart;
+                ++sourceMapStart;
 
                 // Empty elements
                 const additions = resultPosNext - resultPos - 1;
                 for (let j = 0; j < additions; ++j) {
-                    sourceMapping.splice(sourceMappingStart, 0, 0);
-                    ++sourceMappingStart;
+                    sourceMap.insert(sourceMapStart, 0);
+                    ++sourceMapStart;
                 }
 
                 i = iNext;
diff --git a/ext/bg/js/text-source-map.js b/ext/bg/js/text-source-map.js
new file mode 100644
index 00000000..24970978
--- /dev/null
+++ b/ext/bg/js/text-source-map.js
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2020  Alex Yatskov <alex@foosoft.net>
+ * Author: Alex Yatskov <alex@foosoft.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+class TextSourceMap {
+    constructor(source, mapping=null) {
+        this._source = source;
+        this._mapping = (Array.isArray(mapping) ? TextSourceMap._normalizeMapping(mapping) : null);
+    }
+
+    get source() {
+        return this._source;
+    }
+
+    equals(other) {
+        if (this === other) {
+            return true;
+        }
+
+        const source = this._source;
+        if (!(other instanceof TextSourceMap && source === other._source)) {
+            return false;
+        }
+
+        let mapping = this._mapping;
+        let otherMapping = other._mapping;
+        if (mapping === null) {
+            if (otherMapping === null) {
+                return true;
+            }
+            mapping = TextSourceMap._createMapping(source);
+        } else if (otherMapping === null) {
+            otherMapping = TextSourceMap._createMapping(source);
+        }
+
+        const mappingLength = mapping.length;
+        if (mappingLength !== otherMapping.length) {
+            return false;
+        }
+
+        for (let i = 0; i < mappingLength; ++i) {
+            if (mapping[i] !== otherMapping[i]) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    getSourceLength(finalLength) {
+        const mapping = this._mapping;
+        if (mapping === null) {
+            return finalLength;
+        }
+
+        let sourceLength = 0;
+        for (let i = 0; i < finalLength; ++i) {
+            sourceLength += mapping[i];
+        }
+        return sourceLength;
+    }
+
+    combine(index, count) {
+        if (count <= 0) { return; }
+
+        if (this._mapping === null) {
+            this._mapping = TextSourceMap._createMapping(this._source);
+        }
+
+        let sum = this._mapping[index];
+        const parts = this._mapping.splice(index + 1, count);
+        for (const part of parts) {
+            sum += part;
+        }
+        this._mapping[index] = sum;
+    }
+
+    insert(index, ...items) {
+        if (this._mapping === null) {
+            this._mapping = TextSourceMap._createMapping(this._source);
+        }
+
+        this._mapping.splice(index, 0, ...items);
+    }
+
+    static _createMapping(text) {
+        return new Array(text.length).fill(1);
+    }
+
+    static _normalizeMapping(mapping) {
+        const result = [];
+        for (const value of mapping) {
+            result.push(
+                (typeof value === 'number' && Number.isFinite(value)) ?
+                Math.floor(value) :
+                0
+            );
+        }
+        return result;
+    }
+}
diff --git a/ext/bg/js/translator.js b/ext/bg/js/translator.js
index 6f43f7b0..584da02c 100644
--- a/ext/bg/js/translator.js
+++ b/ext/bg/js/translator.js
@@ -19,6 +19,7 @@
 /* global
  * Database
  * Deinflector
+ * TextSourceMap
  * dictEnabledSet
  * dictTagBuildSource
  * dictTagSanitize
@@ -367,17 +368,15 @@ class Translator {
         const used = new Set();
         for (const [halfWidth, numeric, alphabetic, katakana, hiragana] of Translator.getArrayVariants(textOptionVariantArray)) {
             let text2 = text;
-            let sourceMapping = null;
+            const sourceMap = new TextSourceMap(text2);
             if (halfWidth) {
-                if (sourceMapping === null) { sourceMapping = Translator.createTextSourceMapping(text2); }
-                text2 = jp.convertHalfWidthKanaToFullWidth(text2, sourceMapping);
+                text2 = jp.convertHalfWidthKanaToFullWidth(text2, sourceMap);
             }
             if (numeric) {
                 text2 = jp.convertNumericToFullWidth(text2);
             }
             if (alphabetic) {
-                if (sourceMapping === null) { sourceMapping = Translator.createTextSourceMapping(text2); }
-                text2 = jp.convertAlphabeticToKana(text2, sourceMapping);
+                text2 = jp.convertAlphabeticToKana(text2, sourceMap);
             }
             if (katakana) {
                 text2 = jp.convertHiraganaToKatakana(text2);
@@ -391,7 +390,7 @@ class Translator {
                 if (used.has(text2Substring)) { break; }
                 used.add(text2Substring);
                 for (const deinflection of this.deinflector.deinflect(text2Substring)) {
-                    deinflection.rawSource = Translator.getDeinflectionRawSource(text, i, sourceMapping);
+                    deinflection.rawSource = sourceMap.source.substring(0, sourceMap.getSourceLength(i));
                     deinflections.push(deinflection);
                 }
             }
@@ -407,25 +406,6 @@ class Translator {
         }
     }
 
-    static getDeinflectionRawSource(source, length, sourceMapping) {
-        if (sourceMapping === null) {
-            return source.substring(0, length);
-        }
-
-        let result = '';
-        let index = 0;
-        for (let i = 0; i < length; ++i) {
-            const c = sourceMapping[i];
-            result += source.substring(index, index + c);
-            index += c;
-        }
-        return result;
-    }
-
-    static createTextSourceMapping(text) {
-        return new Array(text.length).fill(1);
-    }
-
     async findKanji(text, options) {
         const dictionaries = dictEnabledSet(options);
         const kanjiUnique = new Set();
diff --git a/test/test-japanese.js b/test/test-japanese.js
index c5d220e7..a16a73b7 100644
--- a/test/test-japanese.js
+++ b/test/test-japanese.js
@@ -23,9 +23,11 @@ const vm = new VM();
 vm.execute([
     'mixed/lib/wanakana.min.js',
     'mixed/js/japanese.js',
+    'bg/js/text-source-map.js',
     'bg/js/japanese.js'
 ]);
 const jp = vm.get('jp');
+const TextSourceMap = vm.get('TextSourceMap');
 
 
 function testIsCodePointKanji() {
@@ -262,13 +264,13 @@ function testConvertHalfWidthKanaToFullWidth() {
     ];
 
     for (const [string, expected, expectedSourceMapping] of data) {
-        const sourceMapping = new Array(string.length).fill(1);
+        const sourceMap = new TextSourceMap(string);
         const actual1 = jp.convertHalfWidthKanaToFullWidth(string, null);
-        const actual2 = jp.convertHalfWidthKanaToFullWidth(string, sourceMapping);
+        const actual2 = jp.convertHalfWidthKanaToFullWidth(string, sourceMap);
         assert.strictEqual(actual1, expected);
         assert.strictEqual(actual2, expected);
-        if (Array.isArray(expectedSourceMapping)) {
-            vm.assert.deepStrictEqual(sourceMapping, expectedSourceMapping);
+        if (typeof expectedSourceMapping !== 'undefined') {
+            assert.ok(sourceMap.equals(new TextSourceMap(string, expectedSourceMapping)));
         }
     }
 }
@@ -285,13 +287,13 @@ function testConvertAlphabeticToKana() {
     ];
 
     for (const [string, expected, expectedSourceMapping] of data) {
-        const sourceMapping = new Array(string.length).fill(1);
+        const sourceMap = new TextSourceMap(string);
         const actual1 = jp.convertAlphabeticToKana(string, null);
-        const actual2 = jp.convertAlphabeticToKana(string, sourceMapping);
+        const actual2 = jp.convertAlphabeticToKana(string, sourceMap);
         assert.strictEqual(actual1, expected);
         assert.strictEqual(actual2, expected);
-        if (Array.isArray(expectedSourceMapping)) {
-            vm.assert.deepStrictEqual(sourceMapping, expectedSourceMapping);
+        if (typeof expectedSourceMapping !== 'undefined') {
+            assert.ok(sourceMap.equals(new TextSourceMap(string, expectedSourceMapping)));
         }
     }
 }