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perf(compiler): optimize HtmlEscaper escape path #313

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perf(compiler): optimize HtmlEscaper escape path #313

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940d522
perf(compiler): optimize HtmlEscaper with fastClean implementation
spullara Jul 31, 2026
d7a99b8
refactor(compiler): simplify HtmlEscaper clean flag logic
spullara Jul 31, 2026
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11 changes: 6 additions & 5 deletions compiler/src/main/java/com/github/mustachejava/util/HtmlEscaper.java
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Original file line number Diff line number Diff line change
Expand Up @@ -56,23 +56,24 @@ public class HtmlEscaper {

public static void escape(String value, Writer writer) {
try {
char[] chars = value.toCharArray();
int length = chars.length;
int length = value.length();
int start = 0;
for (int i = 0; i < length; i++) {
char c = chars[i];
char c = value.charAt(i);
char[] escaped;
// We only possibly escape chars in the range 0-96
if (c <= 96 && (escaped = ESC[c]) != null) {
// Write from the last replacement to before this one
if (i > start) writer.write(chars, start, i - start);
if (i > start) writer.write(value, start, i - start);

@augmentcode augmentcode Bot Jul 31, 2026 •
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Writer.write(String, int, int)’s default implementation allocates a new char[] per call; wrappers like LatchedWriter/IndentWriter that only override write(char[], …) may now allocate per clean span and potentially regress perf vs the previous toCharArray+slice approach. Consider validating benchmarks with those writers in the call chain to ensure this stays a win in typical rendering paths.

Other locations where this applies: compiler/src/main/java/com/github/mustachejava/util/HtmlEscaper.java:75

Severity: medium

Other Locations
  • compiler/src/main/java/com/github/mustachejava/util/HtmlEscaper.java:75

Fix This in Augment

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// Write the replacement
writer.write(escaped);
// Move the pointer to the position after replacement
start = i + 1;
}
}
writer.write(chars, start, length - start);
if (start < length) {
writer.write(value, start, length - start);
}
} catch (IOException e) {
throw new MustacheException("Failed to encode value: " + value, e);
}
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