1 files changed, 141 insertions, 0 deletions
diff --git a/browser/extensions/webcompat/lib/about_compat_broker.js b/browser/extensions/webcompat/lib/about_compat_broker.js
new file mode 100644
index 0000000000..56a95aa102
--- /dev/null
+++ b/browser/extensions/webcompat/lib/about_compat_broker.js
@@ -0,0 +1,141 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+/* global browser, module, onMessageFromTab */
+
+class AboutCompatBroker {
+  constructor(bindings) {
+    this._injections = bindings.injections;
+    this._uaOverrides = bindings.uaOverrides;
+    this._shims = bindings.shims;
+
+    if (!this._injections && !this._uaOverrides && !this._shims) {
+      throw new Error("No interventions; about:compat broker is not needed");
+    }
+
+    this.portsToAboutCompatTabs = this.buildPorts();
+    this._injections?.bindAboutCompatBroker(this);
+    this._uaOverrides?.bindAboutCompatBroker(this);
+    this._shims?.bindAboutCompatBroker(this);
+  }
+
+  buildPorts() {
+    const ports = new Set();
+
+    browser.runtime.onConnect.addListener(port => {
+      ports.add(port);
+      port.onDisconnect.addListener(function() {
+        ports.delete(port);
+      });
+    });
+
+    async function broadcast(message) {
+      for (const port of ports) {
+        port.postMessage(message);
+      }
+    }
+
+    return { broadcast };
+  }
+
+  filterOverrides(overrides) {
+    return overrides
+      .filter(override => override.availableOnPlatform)
+      .map(override => {
+        const { id, active, bug, domain, hidden } = override;
+        return { id, active, bug, domain, hidden };
+      });
+  }
+
+  getInterventionById(id) {
+    for (const [type, things] of Object.entries({
+      overrides: this._uaOverrides?.getAvailableOverrides() || [],
+      interventions: this._injections?.getAvailableInjections() || [],
+      shims: this._shims?.getAvailableShims() || [],
+    })) {
+      for (const what of things) {
+        if (what.id === id) {
+          return { type, what };
+        }
+      }
+    }
+    return {};
+  }
+
+  bootup() {
+    onMessageFromTab(msg => {
+      switch (msg.command || msg) {
+        case "toggle": {
+          const id = msg.id;
+          const { type, what } = this.getInterventionById(id);
+          if (!what) {
+            return Promise.reject(
+              `No such override or intervention to toggle: ${id}`
+            );
+          }
+          const active = type === "shims" ? !what.disabledReason : what.active;
+          this.portsToAboutCompatTabs
+            .broadcast({ toggling: id, active })
+            .then(async () => {
+              switch (type) {
+                case "interventions": {
+                  if (active) {
+                    await this._injections?.disableInjection(what);
+                  } else {
+                    await this._injections?.enableInjection(what);
+                  }
+                  break;
+                }
+                case "overrides": {
+                  if (active) {
+                    await this._uaOverrides?.disableOverride(what);
+                  } else {
+                    await this._uaOverrides?.enableOverride(what);
+                  }
+                  break;
+                }
+                case "shims": {
+                  if (active) {
+                    await this._shims?.disableShimForSession(id);
+                  } else {
+                    await this._shims?.enableShimForSession(id);
+                  }
+                  // no need to broadcast the "toggled" signal for shims, as
+                  // they send a shimsUpdated message themselves instead
+                  return;
+                }
+              }
+              this.portsToAboutCompatTabs.broadcast({
+                toggled: id,
+                active: !active,
+              });
+            });
+          break;
+        }
+        case "getAllInterventions": {
+          return Promise.resolve({
+            overrides:
+              (this._uaOverrides?.isEnabled() &&
+                this.filterOverrides(
+                  this._uaOverrides?.getAvailableOverrides()
+                )) ||
+              false,
+            interventions:
+              (this._injections?.isEnabled() &&
+                this.filterOverrides(
+                  this._injections?.getAvailableInjections()
+                )) ||
+              false,
+            shims: this._shims?.getAvailableShims() || false,
+          });
+        }
+      }
+      return undefined;
+    });
+  }
+}
+
+module.exports = AboutCompatBroker;