1 files changed, 251 insertions, 0 deletions
diff --git a/toolkit/components/messaging-system/targeting/Targeting.jsm b/toolkit/components/messaging-system/targeting/Targeting.jsm
new file mode 100644
index 0000000000..5e830b61b3
--- /dev/null
+++ b/toolkit/components/messaging-system/targeting/Targeting.jsm
@@ -0,0 +1,251 @@
+/* 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";
+
+const { XPCOMUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/XPCOMUtils.sys.mjs"
+);
+const { AppConstants } = ChromeUtils.importESModule(
+  "resource://gre/modules/AppConstants.sys.mjs"
+);
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  TelemetryEnvironment: "resource://gre/modules/TelemetryEnvironment.sys.mjs",
+  clearTimeout: "resource://gre/modules/Timer.sys.mjs",
+  setTimeout: "resource://gre/modules/Timer.sys.mjs",
+});
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
+  ASRouterTargeting: "resource://activity-stream/lib/ASRouterTargeting.jsm",
+  FilterExpressions:
+    "resource://gre/modules/components-utils/FilterExpressions.jsm",
+  ClientEnvironment: "resource://normandy/lib/ClientEnvironment.jsm",
+  ClientEnvironmentBase:
+    "resource://gre/modules/components-utils/ClientEnvironment.jsm",
+});
+
+var EXPORTED_SYMBOLS = ["TargetingContext"];
+
+const TARGETING_EVENT_CATEGORY = "messaging_experiments";
+const TARGETING_EVENT_METHOD = "targeting";
+const DEFAULT_TIMEOUT = 5000;
+const ERROR_TYPES = {
+  ATTRIBUTE_ERROR: "attribute_error",
+  TIMEOUT: "attribute_timeout",
+};
+
+const TargetingEnvironment = {
+  get locale() {
+    return lazy.ASRouterTargeting.Environment.locale;
+  },
+
+  get localeLanguageCode() {
+    return lazy.ASRouterTargeting.Environment.localeLanguageCode;
+  },
+
+  get region() {
+    return lazy.ASRouterTargeting.Environment.region;
+  },
+
+  get userId() {
+    return lazy.ClientEnvironment.userId;
+  },
+
+  get version() {
+    return AppConstants.MOZ_APP_VERSION_DISPLAY;
+  },
+
+  get channel() {
+    const { settings } = lazy.TelemetryEnvironment.currentEnvironment;
+    return settings.update.channel;
+  },
+
+  get platform() {
+    return AppConstants.platform;
+  },
+
+  get os() {
+    return lazy.ClientEnvironmentBase.os;
+  },
+};
+
+class TargetingContext {
+  #telemetrySource = null;
+
+  constructor(customContext, options = { source: null }) {
+    if (customContext) {
+      this.ctx = new Proxy(customContext, {
+        get: (customCtx, prop) => {
+          if (prop in TargetingEnvironment) {
+            return TargetingEnvironment[prop];
+          }
+          return customCtx[prop];
+        },
+      });
+    } else {
+      this.ctx = TargetingEnvironment;
+    }
+
+    // Used in telemetry to report where the targeting expression is coming from
+    this.#telemetrySource = options.source;
+
+    // Enable event recording
+    Services.telemetry.setEventRecordingEnabled(TARGETING_EVENT_CATEGORY, true);
+  }
+
+  setTelemetrySource(source) {
+    if (source) {
+      this.#telemetrySource = source;
+    }
+  }
+
+  _sendUndesiredEvent(eventData) {
+    if (this.#telemetrySource) {
+      Services.telemetry.recordEvent(
+        TARGETING_EVENT_CATEGORY,
+        TARGETING_EVENT_METHOD,
+        eventData.event,
+        eventData.value,
+        { source: this.#telemetrySource }
+      );
+    } else {
+      Services.telemetry.recordEvent(
+        TARGETING_EVENT_CATEGORY,
+        TARGETING_EVENT_METHOD,
+        eventData.event,
+        eventData.value
+      );
+    }
+  }
+
+  /**
+   * Wrap each property of context[key] with a Proxy that captures errors and
+   * timeouts
+   *
+   * @param {Object.<string, TargetingGetters> | TargetingGetters} context
+   * @param {string} key Namespace value found in `context` param
+   * @returns {TargetingGetters} Wrapped context where getter report errors and timeouts
+   */
+  createContextWithTimeout(context, key = null) {
+    const timeoutDuration = key ? context[key].timeout : context.timeout;
+    const logUndesiredEvent = (event, key, prop) => {
+      const value = key ? `${key}.${prop}` : prop;
+      this._sendUndesiredEvent({ event, value });
+      Cu.reportError(`${event}: ${value}`);
+    };
+
+    return new Proxy(context, {
+      get(target, prop) {
+        // eslint-disable-next-line no-async-promise-executor
+        return new Promise(async (resolve, reject) => {
+          // Create timeout cb to record attribute resolution taking too long.
+          let timeout = lazy.setTimeout(() => {
+            logUndesiredEvent(ERROR_TYPES.TIMEOUT, key, prop);
+            reject(
+              new Error(
+                `${prop} targeting getter timed out after ${timeoutDuration ||
+                  DEFAULT_TIMEOUT}ms`
+              )
+            );
+          }, timeoutDuration || DEFAULT_TIMEOUT);
+
+          try {
+            resolve(await (key ? target[key][prop] : target[prop]));
+          } catch (error) {
+            logUndesiredEvent(ERROR_TYPES.ATTRIBUTE_ERROR, key, prop);
+            reject(error);
+            Cu.reportError(error);
+          } finally {
+            lazy.clearTimeout(timeout);
+          }
+        });
+      },
+    });
+  }
+
+  /**
+   * Merge all evaluation contexts and wrap the getters with timeouts
+   *
+   * @param {Object.<string, TargetingGetters>[]} contexts
+   * @returns {Object.<string, TargetingGetters>} Object that follows the pattern of `namespace: getters`
+   */
+  mergeEvaluationContexts(contexts) {
+    let context = {};
+    for (let c of contexts) {
+      for (let envNamespace of Object.keys(c)) {
+        // Take the provided context apart, replace it with a proxy
+        context[envNamespace] = this.createContextWithTimeout(c, envNamespace);
+      }
+    }
+
+    return context;
+  }
+
+  /**
+   * Merge multiple TargetingGetters objects without accidentally evaluating
+   *
+   * @param {TargetingGetters[]} ...contexts
+   * @returns {Proxy<TargetingGetters>}
+   */
+  static combineContexts(...contexts) {
+    return new Proxy(
+      {},
+      {
+        get(target, prop) {
+          for (let context of contexts) {
+            if (prop in context) {
+              return context[prop];
+            }
+          }
+
+          return null;
+        },
+      }
+    );
+  }
+
+  /**
+   * Evaluate JEXL expressions with default `TargetingEnvironment` and custom
+   * provided targeting contexts
+   *
+   * @example
+   * eval(
+   *   "ctx.locale == 'en-US' && customCtx.foo == 42",
+   *   { customCtx: { foo: 42 } }
+   * ); // true
+   *
+   * @param {string} expression JEXL expression
+   * @param {Object.<string, TargetingGetters>[]} ...contexts Additional custom context
+   *        objects where the keys act as namespaces for the different getters
+   *
+   * @returns {promise} Evaluation result
+   */
+  eval(expression, ...contexts) {
+    return lazy.FilterExpressions.eval(
+      expression,
+      this.mergeEvaluationContexts([{ ctx: this.ctx }, ...contexts])
+    );
+  }
+
+  /**
+   * Evaluate JEXL expressions with default provided targeting context
+   *
+   * @example
+   * new TargetingContext({ bar: 42 });
+   * evalWithDefault(
+   *   "bar == 42",
+   * ); // true
+   *
+   * @param {string} expression JEXL expression
+   * @returns {promise} Evaluation result
+   */
+  evalWithDefault(expression) {
+    return lazy.FilterExpressions.eval(
+      expression,
+      this.createContextWithTimeout(this.ctx)
+    );
+  }
+}