Cache the `TextDecoder`/`TextEncoder` instances used when compiling/decompiling font-data by Snuffleupagus · Pull Request #21806 · mozilla/pdf.js

Snuffleupagus · 2026-08-20T12:45:35Z

This avoids creating "duplicate" TextDecoder/TextEncoder instances.
For example, when rendering all 1310 pages of the pdf.pdf document (from the test-suite) this patch reduces the number of TextDecoder/TextEncoder instances from 73 each to just a single one each.

Note: Compared to PR #21801 the reduction is obviously much smaller, however it still seems worthwhile to avoid unnecessary object creation.

codecov-commenter · 2026-08-20T12:47:15Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.17%. Comparing base (e051279) to head (ea5ecb0).

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #21806      +/-   ##
==========================================
- Coverage   90.19%   90.17%   -0.02%     
==========================================
  Files         264      264              
  Lines       67324    67327       +3     
==========================================
- Hits        60721    60715       -6     
- Misses       6603     6612       +9

Flag	Coverage Δ
browsertest	`66.30% <100.00%> (-0.02%)`	⬇️
fonttest	`8.91% <0.00%> (-0.01%)`	⬇️
integrationtest	`69.39% <100.00%> (-0.01%)`	⬇️
unittest	`58.33% <100.00%> (-0.02%)`	⬇️
unittestcli	`56.90% <100.00%> (-0.02%)`	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

…ecompiling font-data This avoids creating "duplicate" `TextDecoder`/`TextEncoder` instances. For example, when rendering all 1310 pages of the `pdf.pdf` document (from the test-suite) this patch reduces the number of `TextDecoder`/`TextEncoder` instances from `73` *each* to just a single one each. *Note:* Compared to PR 21801 the reduction is obviously much smaller, however it still seems worthwhile to avoid unnecessary object creation.

Snuffleupagus · 2026-08-20T13:08:08Z

/botio browsertest

moz-tools-bot · 2026-08-20T13:08:10Z

From: Bot.io (Windows)

Received

Command cmd_browsertest from @Snuffleupagus received. Current queue size: 0

Live output at: http://54.193.163.58:8877/6845a319ab9942d/output.txt

moz-tools-bot · 2026-08-20T13:08:10Z

From: Bot.io (Linux m4)

Received

Command cmd_browsertest from @Snuffleupagus received. Current queue size: 0

Live output at: http://54.241.84.105:8877/7a41e42ff594470/output.txt

moz-tools-bot · 2026-08-20T13:26:16Z

From: Bot.io (Linux m4)

Success

Full output at http://54.241.84.105:8877/7a41e42ff594470/output.txt

Total script time: 18.07 mins

Regression tests: Passed

moz-tools-bot · 2026-08-20T13:31:19Z

From: Bot.io (Windows)

Success

Full output at http://54.193.163.58:8877/6845a319ab9942d/output.txt

Total script time: 23.12 mins

Regression tests: Passed

timvandermeij · 2026-08-20T20:07:11Z

Makes sense; thank you for optimizing this!

Snuffleupagus added the core label Aug 20, 2026

Snuffleupagus temporarily deployed to code-coverage August 20, 2026 12:45 — with GitHub Actions Inactive