Bug 1749769 - [devtools] Lazy load target legacy listeners. r=nchevobbe

Differential Revision: https://phabricator.services.mozilla.com/D135832

devtools/client/webconsole/test/node/mocha-test-setup.js

@@ -57,6 +57,10 @@ global.loader = {
       "devtools/client/shared/telemetry",
       "devtools/client/shared/screenshot",
       "devtools/client/shared/focus",
+      "devtools/shared/commands/target/legacy-target-watchers/legacy-processes-watcher",
+      "devtools/shared/commands/target/legacy-target-watchers/legacy-workers-watcher",
+      "devtools/shared/commands/target/legacy-target-watchers/legacy-sharedworkers-watcher",
+      "devtools/shared/commands/target/legacy-target-watchers/legacy-serviceworkers-watcher",
     ];
     if (!excluded.includes(path)) {
       if (!Array.isArray(names)) {
@@ -64,8 +68,13 @@ global.loader = {
       }
 
       for (const name of names) {
-        const module = require(path);
-        global[name] = destruct ? module[name] : module;
+        Object.defineProperty(global, name, {
+          get() {
+            const module = require(path);
+            return destruct ? module[name] : module;
+          },
+          configurable: true,
+        });
       }
     }
   },

devtools/shared/commands/target/legacy-target-watchers/legacy-processes-watcher.js

@@ -69,4 +69,4 @@ class LegacyProcessesWatcher {
   }
 }
 
-module.exports = { LegacyProcessesWatcher };
+module.exports = LegacyProcessesWatcher;

devtools/shared/commands/target/legacy-target-watchers/legacy-serviceworkers-watcher.js

@@ -7,9 +7,7 @@
 // eslint-disable-next-line mozilla/reject-some-requires
 const { WorkersListener } = require("devtools/client/shared/workers-listener");
 
-const {
-  LegacyWorkersWatcher,
-} = require("devtools/shared/commands/target/legacy-target-watchers/legacy-workers-watcher");
+const LegacyWorkersWatcher = require("devtools/shared/commands/target/legacy-target-watchers/legacy-workers-watcher");
 
 class LegacyServiceWorkersWatcher extends LegacyWorkersWatcher {
   // Holds the current target URL object
@@ -317,4 +315,4 @@ class LegacyServiceWorkersWatcher extends LegacyWorkersWatcher {
   }
 }
 
-module.exports = { LegacyServiceWorkersWatcher };
+module.exports = LegacyServiceWorkersWatcher;

devtools/shared/commands/target/legacy-target-watchers/legacy-sharedworkers-watcher.js

@@ -4,9 +4,7 @@
 
 "use strict";
 
-const {
-  LegacyWorkersWatcher,
-} = require("devtools/shared/commands/target/legacy-target-watchers/legacy-workers-watcher");
+const LegacyWorkersWatcher = require("devtools/shared/commands/target/legacy-target-watchers/legacy-workers-watcher");
 
 class LegacySharedWorkersWatcher extends LegacyWorkersWatcher {
   // Flag used from the parent class to listen to process targets.
@@ -18,4 +16,4 @@ class LegacySharedWorkersWatcher extends LegacyWorkersWatcher {
   }
 }
 
-module.exports = { LegacySharedWorkersWatcher };
+module.exports = LegacySharedWorkersWatcher;

devtools/shared/commands/target/legacy-target-watchers/legacy-workers-watcher.js

@@ -4,9 +4,7 @@
 
 "use strict";
 
-const {
-  LegacyProcessesWatcher,
-} = require("devtools/shared/commands/target/legacy-target-watchers/legacy-processes-watcher");
+const LegacyProcessesWatcher = require("devtools/shared/commands/target/legacy-target-watchers/legacy-processes-watcher");
 
 class LegacyWorkersWatcher {
   constructor(targetCommand, onTargetAvailable, onTargetDestroyed) {
@@ -237,4 +235,4 @@ class LegacyWorkersWatcher {
   }
 }
 
-module.exports = { LegacyWorkersWatcher };
+module.exports = LegacyWorkersWatcher;

devtools/shared/commands/target/target-command.js

@@ -9,19 +9,6 @@ const EventEmitter = require("devtools/shared/event-emitter");
 
 const BROWSERTOOLBOX_FISSION_ENABLED = "devtools.browsertoolbox.fission";
 
-const {
-  LegacyProcessesWatcher,
-} = require("devtools/shared/commands/target/legacy-target-watchers/legacy-processes-watcher");
-const {
-  LegacyServiceWorkersWatcher,
-} = require("devtools/shared/commands/target/legacy-target-watchers/legacy-serviceworkers-watcher");
-const {
-  LegacySharedWorkersWatcher,
-} = require("devtools/shared/commands/target/legacy-target-watchers/legacy-sharedworkers-watcher");
-const {
-  LegacyWorkersWatcher,
-} = require("devtools/shared/commands/target/legacy-target-watchers/legacy-workers-watcher");
-
 class TargetCommand extends EventEmitter {
   #selectedTargetFront;
   /**
@@ -88,29 +75,7 @@ class TargetCommand extends EventEmitter {
     this._onTargetDestroyed = this._onTargetDestroyed.bind(this);
     this._onTargetSelected = this._onTargetSelected.bind(this);
 
-    this.legacyImplementation = {
-      process: new LegacyProcessesWatcher(
-        this,
-        this._onTargetAvailable,
-        this._onTargetDestroyed
-      ),
-      worker: new LegacyWorkersWatcher(
-        this,
-        this._onTargetAvailable,
-        this._onTargetDestroyed
-      ),
-      shared_worker: new LegacySharedWorkersWatcher(
-        this,
-        this._onTargetAvailable,
-        this._onTargetDestroyed
-      ),
-      service_worker: new LegacyServiceWorkersWatcher(
-        this,
-        this._onTargetAvailable,
-        this._onTargetDestroyed,
-        this.commands
-      ),
-    };
+    this.legacyImplementation = {};
 
     // Public flag to allow listening for workers even if the fission pref is off
     // This allows listening for workers in the content toolbox outside of fission contexts
@@ -466,7 +431,16 @@ class TargetCommand extends EventEmitter {
         if (!isTargetSwitching) {
           await this.watcherFront.watchTargets(type);
         }
-      } else if (this.legacyImplementation[type]) {
+      } else if (LegacyTargetWatchers[type]) {
+        // Instantiate the legacy listener only once for each TargetCommand, and reuse it if we stop and restart listening
+        if (!this.legacyImplementation[type]) {
+          this.legacyImplementation[type] = new LegacyTargetWatchers[type](
+            this,
+            this._onTargetAvailable,
+            this._onTargetDestroyed,
+            this.commands
+          );
+        }
         await this.legacyImplementation[type].listen();
       } else {
         throw new Error(`Unsupported target type '${type}'`);
@@ -1087,4 +1061,26 @@ TargetCommand.ALL_TYPES = TargetCommand.prototype.ALL_TYPES = Object.values(
   TargetCommand.TYPES
 );
 
+const LegacyTargetWatchers = {};
+loader.lazyRequireGetter(
+  LegacyTargetWatchers,
+  TargetCommand.TYPES.PROCESS,
+  "devtools/shared/commands/target/legacy-target-watchers/legacy-processes-watcher"
+);
+loader.lazyRequireGetter(
+  LegacyTargetWatchers,
+  TargetCommand.TYPES.WORKER,
+  "devtools/shared/commands/target/legacy-target-watchers/legacy-workers-watcher"
+);
+loader.lazyRequireGetter(
+  LegacyTargetWatchers,
+  TargetCommand.TYPES.SHARED_WORKER,
+  "devtools/shared/commands/target/legacy-target-watchers/legacy-sharedworkers-watcher"
+);
+loader.lazyRequireGetter(
+  LegacyTargetWatchers,
+  TargetCommand.TYPES.SERVICE_WORKER,
+  "devtools/shared/commands/target/legacy-target-watchers/legacy-serviceworkers-watcher"
+);
+
 module.exports = TargetCommand;