Reimplement helpers.forEachInlineCodeSpan for ~11% time reduction mea…

…sured via profile-fixture.mjs on GitHub Codespaces.
DavidAnson · Jun 19, 2022 · 6e8a073 · 6e8a073
1 parent d177ee2
commit 6e8a073
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Showing 3 changed files with 67 additions and 116 deletions.
diff --git a/demo/markdownlint-browser.js b/demo/markdownlint-browser.js
@@ -437,67 +437,39 @@ module.exports.forEachHeading = function forEachHeading(params, handler) {
  * @returns {void}
  */
 function forEachInlineCodeSpan(input, handler) {
-    let currentLine = 0;
-    let currentColumn = 0;
-    let index = 0;
-    while (index < input.length) {
-        let startIndex = -1;
-        let startLine = -1;
-        let startColumn = -1;
-        let tickCount = 0;
-        let currentTicks = 0;
-        // Deliberate <= so trailing 0 completes the last span (ex: "text `code`")
-        // False-positive for js/index-out-of-bounds
-        for (; index <= input.length; index++) {
-            const char = input[index];
-            // Parse backtick open/close
-            if (char === "`") {
-                // Count backticks at start or end of code span
-                currentTicks++;
-                if ((startIndex === -1) || (startColumn === -1)) {
-                    startIndex = index + 1;
-                }
-            }
-            else {
-                if ((startIndex >= 0) &&
-                    (startColumn >= 0) &&
-                    (tickCount === currentTicks)) {
-                    // Found end backticks; invoke callback for code span
-                    handler(input.substring(startIndex, index - currentTicks), startLine, startColumn, tickCount);
-                    startIndex = -1;
-                    startColumn = -1;
-                }
-                else if ((startIndex >= 0) && (startColumn === -1)) {
-                    // Found start backticks
-                    tickCount = currentTicks;
-                    startLine = currentLine;
-                    startColumn = currentColumn;
+    const backtickRe = /`+/g;
+    let match = null;
+    const backticksLengthAndIndex = [];
+    while ((match = backtickRe.exec(input)) !== null) {
+        backticksLengthAndIndex.push([match[0].length, match.index]);
+    }
+    const newLinesIndex = [];
+    while ((match = newLineRe.exec(input)) !== null) {
+        newLinesIndex.push(match.index);
+    }
+    let lineIndex = 0;
+    let lineStartIndex = 0;
+    let k = 0;
+    for (let i = 0; i < backticksLengthAndIndex.length - 1; i++) {
+        const [startLength, startIndex] = backticksLengthAndIndex[i];
+        if ((startIndex === 0) || (input[startIndex - 1] !== "\\")) {
+            for (let j = i + 1; j < backticksLengthAndIndex.length; j++) {
+                const [endLength, endIndex] = backticksLengthAndIndex[j];
+                if (startLength === endLength) {
+                    for (; k < newLinesIndex.length; k++) {
+                        const newLineIndex = newLinesIndex[k];
+                        if (startIndex < newLineIndex) {
+                            break;
+                        }
+                        lineIndex++;
+                        lineStartIndex = newLineIndex + 1;
+                    }
+                    const columnIndex = startIndex - lineStartIndex + startLength;
+                    handler(input.slice(startIndex + startLength, endIndex), lineIndex, columnIndex, startLength);
+                    i = j;
+                    break;
                 }
-                // Not in backticks
-                currentTicks = 0;
-            }
-            if (char === "\n") {
-                // On next line
-                currentLine++;
-                currentColumn = 0;
-            }
-            else if ((char === "\\") &&
-                ((startIndex === -1) || (startColumn === -1)) &&
-                (input[index + 1] !== "\n")) {
-                // Escape character outside code, skip next
-                index++;
-                currentColumn += 2;
             }
-            else {
-                // On next column
-                currentColumn++;
-            }
-        }
-        if (startIndex >= 0) {
-            // Restart loop after unmatched start backticks (ex: "`text``code``")
-            index = startIndex;
-            currentLine = startLine;
-            currentColumn = startColumn;
         }
     }
 }

diff --git a/helpers/helpers.js b/helpers/helpers.js
@@ -437,65 +437,44 @@ module.exports.forEachHeading = function forEachHeading(params, handler) {
  * @returns {void}
  */
 function forEachInlineCodeSpan(input, handler) {
-  let currentLine = 0;
-  let currentColumn = 0;
-  let index = 0;
-  while (index < input.length) {
-    let startIndex = -1;
-    let startLine = -1;
-    let startColumn = -1;
-    let tickCount = 0;
-    let currentTicks = 0;
-    // Deliberate <= so trailing 0 completes the last span (ex: "text `code`")
-    // False-positive for js/index-out-of-bounds
-    for (; index <= input.length; index++) {
-      const char = input[index];
-      // Parse backtick open/close
-      if (char === "`") {
-        // Count backticks at start or end of code span
-        currentTicks++;
-        if ((startIndex === -1) || (startColumn === -1)) {
-          startIndex = index + 1;
-        }
-      } else {
-        if ((startIndex >= 0) &&
-          (startColumn >= 0) &&
-          (tickCount === currentTicks)) {
-          // Found end backticks; invoke callback for code span
+  const backtickRe = /`+/g;
+  let match = null;
+  const backticksLengthAndIndex = [];
+  while ((match = backtickRe.exec(input)) !== null) {
+    backticksLengthAndIndex.push([ match[0].length, match.index ]);
+  }
+  const newLinesIndex = [];
+  while ((match = newLineRe.exec(input)) !== null) {
+    newLinesIndex.push(match.index);
+  }
+  let lineIndex = 0;
+  let lineStartIndex = 0;
+  let k = 0;
+  for (let i = 0; i < backticksLengthAndIndex.length - 1; i++) {
+    const [ startLength, startIndex ] = backticksLengthAndIndex[i];
+    if ((startIndex === 0) || (input[startIndex - 1] !== "\\")) {
+      for (let j = i + 1; j < backticksLengthAndIndex.length; j++) {
+        const [ endLength, endIndex ] = backticksLengthAndIndex[j];
+        if (startLength === endLength) {
+          for (; k < newLinesIndex.length; k++) {
+            const newLineIndex = newLinesIndex[k];
+            if (startIndex < newLineIndex) {
+              break;
+            }
+            lineIndex++;
+            lineStartIndex = newLineIndex + 1;
+          }
+          const columnIndex = startIndex - lineStartIndex + startLength;
           handler(
-            input.substring(startIndex, index - currentTicks),
-            startLine, startColumn, tickCount);
-          startIndex = -1;
-          startColumn = -1;
-        } else if ((startIndex >= 0) && (startColumn === -1)) {
-          // Found start backticks
-          tickCount = currentTicks;
-          startLine = currentLine;
-          startColumn = currentColumn;
+            input.slice(startIndex + startLength, endIndex),
+            lineIndex,
+            columnIndex,
+            startLength
+          );
+          i = j;
+          break;
         }
-        // Not in backticks
-        currentTicks = 0;
       }
-      if (char === "\n") {
-        // On next line
-        currentLine++;
-        currentColumn = 0;
-      } else if ((char === "\\") &&
-        ((startIndex === -1) || (startColumn === -1)) &&
-        (input[index + 1] !== "\n")) {
-        // Escape character outside code, skip next
-        index++;
-        currentColumn += 2;
-      } else {
-        // On next column
-        currentColumn++;
-      }
-    }
-    if (startIndex >= 0) {
-      // Restart loop after unmatched start backticks (ex: "`text``code``")
-      index = startIndex;
-      currentLine = startLine;
-      currentColumn = startColumn;
     }
   }
 }

diff --git a/test/markdownlint-test-helpers.js b/test/markdownlint-test-helpers.js
@@ -391,7 +391,7 @@ test("forEachInlineCodeSpan", (t) => {
       t.is(column, expectedColumn, input);
       t.is(ticks, expectedTicks, input);
     });
-    t.is(expecteds.length, 0, "length");
+    t.is(expecteds.shift(), undefined, input);
   }
 });