v8_inspector::StringView can either be one-byte or two-byte strings.
Node has currently two places where it's unconditionally assumed that
it's a two-byte StringView.

This requires the upstream V8 inspector to unnecessarily create
a copy of the string:

https://source.chromium.org/chromium/chromium/src/+/main:v8/src/inspector/v8-inspector-session-impl.cc;l=192-199;drc=05bacd38e7a31e92afe0fd66081dfa2cc03b934a

This is particularly slow, especially for large CDP messages, as the
serialized JSON is iterated 8-bit char by 8-bit char and each one
widened to a 16-bit char.

This PR introduces a small helper that correctly converts a StringView
to a v8::String instance honoring the "is8Bit" flag. This allows
upstream V8 to remove the unnecessary widening copy.

PR-URL: #52372
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Minwoo Jung <nodecorelab@gmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>

v8_inspector::StringView can either be one-byte or two-byte strings.
Node has currently two places where it's unconditionally assumed that
it's a two-byte StringView.

This requires the upstream V8 inspector to unnecessarily create
a copy of the string:

https://source.chromium.org/chromium/chromium/src/+/main:v8/src/inspector/v8-inspector-session-impl.cc;l=192-199;drc=05bacd38e7a31e92afe0fd66081dfa2cc03b934a

This is particularly slow, especially for large CDP messages, as the
serialized JSON is iterated 8-bit char by 8-bit char and each one
widened to a 16-bit char.

This PR introduces a small helper that correctly converts a StringView
to a v8::String instance honoring the "is8Bit" flag. This allows
upstream V8 to remove the unnecessary widening copy.

PR-URL: #52372
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Minwoo Jung <nodecorelab@gmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>

v8_inspector::StringView can either be one-byte or two-byte strings.
Node has currently two places where it's unconditionally assumed that
it's a two-byte StringView.

This requires the upstream V8 inspector to unnecessarily create
a copy of the string:

https://source.chromium.org/chromium/chromium/src/+/main:v8/src/inspector/v8-inspector-session-impl.cc;l=192-199;drc=05bacd38e7a31e92afe0fd66081dfa2cc03b934a

This is particularly slow, especially for large CDP messages, as the
serialized JSON is iterated 8-bit char by 8-bit char and each one
widened to a 16-bit char.

This PR introduces a small helper that correctly converts a StringView
to a v8::String instance honoring the "is8Bit" flag. This allows
upstream V8 to remove the unnecessary widening copy.

PR-URL: #52372
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Minwoo Jung <nodecorelab@gmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>

v8_inspector::StringView can either be one-byte or two-byte strings.
Node has currently two places where it's unconditionally assumed that
it's a two-byte StringView.

This requires the upstream V8 inspector to unnecessarily create
a copy of the string:

https://source.chromium.org/chromium/chromium/src/+/main:v8/src/inspector/v8-inspector-session-impl.cc;l=192-199;drc=05bacd38e7a31e92afe0fd66081dfa2cc03b934a

This is particularly slow, especially for large CDP messages, as the
serialized JSON is iterated 8-bit char by 8-bit char and each one
widened to a 16-bit char.

This PR introduces a small helper that correctly converts a StringView
to a v8::String instance honoring the "is8Bit" flag. This allows
upstream V8 to remove the unnecessary widening copy.

PR-URL: #52372
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Minwoo Jung <nodecorelab@gmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>

v8_inspector::StringView can either be one-byte or two-byte strings.
Node has currently two places where it's unconditionally assumed that
it's a two-byte StringView.

This requires the upstream V8 inspector to unnecessarily create
a copy of the string:

https://source.chromium.org/chromium/chromium/src/+/main:v8/src/inspector/v8-inspector-session-impl.cc;l=192-199;drc=05bacd38e7a31e92afe0fd66081dfa2cc03b934a

This is particularly slow, especially for large CDP messages, as the
serialized JSON is iterated 8-bit char by 8-bit char and each one
widened to a 16-bit char.

This PR introduces a small helper that correctly converts a StringView
to a v8::String instance honoring the "is8Bit" flag. This allows
upstream V8 to remove the unnecessary widening copy.

PR-URL: #52372
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Minwoo Jung <nodecorelab@gmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>

v8_inspector::StringView can either be one-byte or two-byte strings.
Node has currently two places where it's unconditionally assumed that
it's a two-byte StringView.

This requires the upstream V8 inspector to unnecessarily create
a copy of the string:

https://source.chromium.org/chromium/chromium/src/+/main:v8/src/inspector/v8-inspector-session-impl.cc;l=192-199;drc=05bacd38e7a31e92afe0fd66081dfa2cc03b934a

This is particularly slow, especially for large CDP messages, as the
serialized JSON is iterated 8-bit char by 8-bit char and each one
widened to a 16-bit char.

This PR introduces a small helper that correctly converts a StringView
to a v8::String instance honoring the "is8Bit" flag. This allows
upstream V8 to remove the unnecessary widening copy.

PR-URL: #52372
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Minwoo Jung <nodecorelab@gmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>

Upstream Node.js was missing a check for 'is8Bit' making it necessary
to always use 16-bit wide chars when serializing CDP messages.

We fixed this upstream (nodejs/node#52372) so
now we can remove the widening copy.

Bug: None
Change-Id: I1f0b15e0ece7c0987dfcbeeaf913e9d76cda8ba8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/6478571
Reviewed-by: Eric Leese <leese@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/main@{#101360}