1521540 - improve sourceMapURL performance

Status: RESOLVED FIXED

(DevTools :: Debugger, enhancement, P2)

Description

[Jason Laster [:jlast]]

General Debugger slowness (https://github.com/devtools-html/debugger.html/issues/7734) helped us find a slow path in sourceMapURL

diff --git a/devtools/server/actors/source.js b/devtools/server/actors/source.js
index 02fa3f38f1e7..13d4f13b908a 100644
--- a/devtools/server/actors/source.js
+++ b/devtools/server/actors/source.js
@@ -187,6 +187,15 @@ const SourceActor = ActorClassWithSpec(sourceSpec, {
     return this._addonPath;
   },

+  get sourceMapURL() {
+    if (this._sourceMapURL) {
+      return this._sourceMapURL;
+    }
+
+    this._sourceMapURL = source ? source.sourceMapURL : null
+    return this._sourceMapURL;
+  },
+
   get isCacheEnabled() {
     if (this.threadActor._parent._getCacheDisabled) {
       return !this.threadActor._parent._getCacheDisabled();
@@ -209,7 +218,7 @@ const SourceActor = ActorClassWithSpec(sourceSpec, {
       addonID: this._addonID,
       addonPath: this._addonPath,
       isBlackBoxed: this.threadActor.sources.isBlackBoxed(this.url),
-      sourceMapURL: source ? source.sourceMapURL : null,
+      sourceMapURL: this.sourceMapURL,
       introductionUrl: introductionUrl ? introductionUrl.split(" -> ").pop() : null,
       introductionType: source ? source.introductionType : null,
     };

we could also memoize here which would be better?

Comment 1

[Jason Laster [:jlast]]

Attachment: sourcemapurl.png

Comment 2

[Jason Laster [:jlast]]

I'm going to re-purpose this bug and focus on the fact that serializing the source actor for frame forms can be slow because of sourceMapURL.

Comment 3

[Jason Laster [:jlast]]

Attachment: Bug 1521540 - improve sourceMapURL performance. r=lsmyth

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/e3f2ecc94174
Replace Frame.source form with Frame.actor. r=lsmyth

Comment 5

[Andrei Ciure[:aciure]]

https://hg.mozilla.org/mozilla-central/rev/e3f2ecc94174