Improves performance of blame annotations

Author: eamodio

CHANGELOG.md

@@ -9,6 +9,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/) and this p
 - Adds *Checkout Commit (via Terminal)* command (`gitlens.terminalCheckoutCommit`) to commit node(s) of the *GitLens* explorer — closes [#463](https://github.com/eamodio/vscode-gitlens/issues/463)
 
 ### Changed
+- Improves performance of blame annotation rendering
 - Changes commit search by sha to jump directly to the commit (if one is found), rather than having to click through to the commit
 - Updates settings descriptions to better support the new settings editor in vscode
 - Changes *Rebase to Commit (via Terminal)* command (`gitlens.terminalRebaseCommit`) to apply to all commit node(s) of the *GitLens* explorer

src/annotations/annotations.ts

@@ -288,7 +288,7 @@ export class Annotations {
 
         if (width >= 0) {
             // Add the width of the template string (without tokens)
-            width += Strings.width(Strings.interpolate(format, undefined));
+            width += Strings.getWidth(Strings.interpolate(format, undefined));
             // If we have some width, add a bit of padding
             if (width > 0) {
                 width += 3;

src/annotations/gutterBlameAnnotationProvider.ts

@@ -68,7 +68,7 @@ export class GutterBlameAnnotationProvider extends BlameAnnotationProviderBase {
                         before: {
                             ...gutter.renderOptions!.before,
                             contentText: GlyphChars.Space.repeat(
-                                Strings.width(gutter.renderOptions!.before!.contentText!)
+                                Strings.getWidth(gutter.renderOptions!.before!.contentText!)
                             )
                         }
                     };

src/git/formatters/formatter.ts

@@ -52,37 +52,39 @@ export abstract class Formatter<TItem = any, TOptions extends IFormatOptions = I
 
         let max = options.truncateTo;
 
-        const width = Strings.width(s);
         if (max === undefined) {
             if (this.collapsableWhitespace === 0) return s;
 
+            const width = Strings.getWidth(s);
+
             // If we have left over whitespace make sure it gets re-added
             const diff = this.collapsableWhitespace - width;
             this.collapsableWhitespace = 0;
 
             if (diff <= 0) return s;
             if (options.truncateTo === undefined) return s;
-            return Strings.padLeft(s, diff);
+            return Strings.padLeft(s, diff, undefined, width);
         }
 
         max += this.collapsableWhitespace;
         this.collapsableWhitespace = 0;
 
+        const width = Strings.getWidth(s);
         const diff = max - width;
         if (diff > 0) {
             if (options.collapseWhitespace) {
                 this.collapsableWhitespace = diff;
             }
 
-            if (options.padDirection === 'left') return Strings.padLeft(s, max);
+            if (options.padDirection === 'left') return Strings.padLeft(s, max, undefined, width);
 
             if (options.collapseWhitespace) {
                 max -= diff;
             }
-            return Strings.padRight(s, max);
+            return Strings.padRight(s, max, undefined, width);
         }
 
-        if (diff < 0) return Strings.truncate(s, max);
+        if (diff < 0) return Strings.truncate(s, max, undefined, width);
 
         return s;
     }

src/system/string.ts

@@ -74,37 +74,37 @@ export namespace Strings {
         return `${before === 0 ? '' : padding.repeat(before)}${s}${after === 0 ? '' : padding.repeat(after)}`;
     }
 
-    export function padLeft(s: string, padTo: number, padding: string = '\u00a0') {
-        const diff = padTo - width(s);
+    export function padLeft(s: string, padTo: number, padding: string = '\u00a0', width?: number) {
+        const diff = padTo - (width || getWidth(s));
         return diff <= 0 ? s : padding.repeat(diff) + s;
     }
 
-    export function padLeftOrTruncate(s: string, max: number, padding?: string) {
-        const len = width(s);
-        if (len < max) return padLeft(s, max, padding);
-        if (len > max) return truncate(s, max);
+    export function padLeftOrTruncate(s: string, max: number, padding?: string, width?: number) {
+        width = width || getWidth(s);
+        if (width < max) return padLeft(s, max, padding, width);
+        if (width > max) return truncate(s, max, undefined, width);
         return s;
     }
 
-    export function padRight(s: string, padTo: number, padding: string = '\u00a0') {
-        const diff = padTo - width(s);
+    export function padRight(s: string, padTo: number, padding: string = '\u00a0', width?: number) {
+        const diff = padTo - (width || getWidth(s));
         return diff <= 0 ? s : s + padding.repeat(diff);
     }
 
-    export function padOrTruncate(s: string, max: number, padding?: string) {
+    export function padOrTruncate(s: string, max: number, padding?: string, width?: number) {
         const left = max < 0;
         max = Math.abs(max);
 
-        const len = width(s);
-        if (len < max) return left ? padLeft(s, max, padding) : padRight(s, max, padding);
-        if (len > max) return truncate(s, max);
+        width = width || getWidth(s);
+        if (width < max) return left ? padLeft(s, max, padding, width) : padRight(s, max, padding, width);
+        if (width > max) return truncate(s, max, undefined, width);
         return s;
     }
 
-    export function padRightOrTruncate(s: string, max: number, padding?: string) {
-        const len = width(s);
-        if (len < max) return padRight(s, max, padding);
-        if (len > max) return truncate(s, max);
+    export function padRightOrTruncate(s: string, max: number, padding?: string, width?: number) {
+        width = width || getWidth(s);
+        if (width < max) return padRight(s, max, padding, width);
+        if (width > max) return truncate(s, max);
         return s;
     }
 
@@ -122,18 +122,18 @@ export namespace Strings {
             .digest(encoding);
     }
 
-    export function truncate(s: string, truncateTo: number, ellipsis: string = '\u2026') {
+    export function truncate(s: string, truncateTo: number, ellipsis: string = '\u2026', width?: number) {
         if (!s) return s;
 
-        const len = width(s);
-        if (len <= truncateTo) return s;
-        if (len === s.length) return `${s.substring(0, truncateTo - 1)}${ellipsis}`;
+        width = width || getWidth(s);
+        if (width <= truncateTo) return s;
+        if (width === s.length) return `${s.substring(0, truncateTo - 1)}${ellipsis}`;
 
         // Skip ahead to start as far as we can by assuming all the double-width characters won't be truncated
-        let chars = Math.floor(truncateTo / (len / s.length));
-        let count = width(s.substring(0, chars));
+        let chars = Math.floor(truncateTo / (width / s.length));
+        let count = getWidth(s.substring(0, chars));
         while (count < truncateTo) {
-            count += width(s[chars++]);
+            count += getWidth(s[chars++]);
         }
 
         if (count >= truncateTo) {
@@ -144,9 +144,13 @@ export namespace Strings {
     }
 
     const ansiRegex = /[\\u001B\\u009B][[\\]()#;?]*(?:(?:(?:[a-zA-Z\\d]*(?:;[a-zA-Z\\d]*)*)?\\u0007)|(?:(?:\\d{1,4}(?:;\\d{0,4})*)?[\\dA-PRZcf-ntqry=><~]))/g;
+    const containsNonAsciiRegex = /[^\x20-\x7F\u00a0\u2026]/;
 
-    export function width(s: string): number {
-        if (!s || s.length === 0) return 0;
+    export function getWidth(s: string): number {
+        if (s == null || s.length === 0) return 0;
+
+        // Shortcut to avoid needless string `RegExp`s, replacements, and allocations
+        if (!containsNonAsciiRegex.test(s)) return s.length;
 
         s = s.replace(ansiRegex, '');