nodejs · sam-github · Feb 14, 2020 · Feb 14, 2020 · Feb 14, 2020
diff --git a/deps/zlib/README.md b/deps/zlib/README.md
diff --git a/deps/zlib/google/test/data/create_test_zip.sh b/deps/zlib/google/test/data/create_test_zip.sh
diff --git a/doc/guides/maintaining-zlib.md b/doc/guides/maintaining-zlib.md
@@ -0,0 +1,34 @@
+# Maintaining zlib
+
+This copy of zlib comes from the Chromium team's zlib fork which incorporated
+performance improvements not currently available in standard zlib.
+
+## Updating zlib
+
+Update zlib:
+```shell
+git clone https://chromium.googlesource.com/chromium/src/third_party/zlib
+cp deps/zlib/zlib.gyp deps/zlib/win32/zlib.def deps
+rm -rf deps/zlib zlib/.git
+mv zlib deps/
+mv deps/zlib.gyp deps/zlib/
+mkdir deps/zlib/win32
+mv deps/zlib.def deps/zlib/win32
+sed -i -- 's_^#include "chromeconf.h"_//#include "chromeconf.h"_' deps/zlib/zconf.h
+```
+
+Check that Node.js still builds and tests.
+
+It may be necessary to update deps/zlib/zlib.gyp if any significant changes have
+occurred upstream.
+
+## Commiting zlib
+
+Add zlib: `git add --all deps/zlib`
+
+Commit the changes with a message like
+```text
+deps: update zlib to upstream d7f3ca9
+
+Updated as described in doc/guides/maintaining-zlib.md.
+```