1 files changed, 127 insertions, 0 deletions
diff --git a/toolkit/components/forgetaboutsite/ForgetAboutSite.sys.mjs b/toolkit/components/forgetaboutsite/ForgetAboutSite.sys.mjs
new file mode 100644
index 0000000000..603d121403
--- /dev/null
+++ b/toolkit/components/forgetaboutsite/ForgetAboutSite.sys.mjs
@@ -0,0 +1,127 @@
+/* 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/. */
+
+export var ForgetAboutSite = {
+  /**
+   * Clear data associated with a base domain. This includes partitioned storage
+   * associated with the domain. If a base domain can not be computed from
+   * aDomainOrHost, data will be cleared by host instead.
+   *
+   * @param {string} aDomainOrHost - Domain or host to clear data for. Will be
+   * converted to base domain if needed.
+   * @returns {Promise} - Resolves once all matching data has been cleared.
+   * Throws if any of the internal cleaners fail.
+   */
+  async removeDataFromBaseDomain(aDomainOrHost) {
+    if (!aDomainOrHost) {
+      throw new Error("aDomainOrHost can not be empty.");
+    }
+
+    let baseDomain;
+    try {
+      baseDomain = Services.eTLD.getBaseDomainFromHost(aDomainOrHost);
+    } catch (e) {}
+
+    let errorCount;
+    if (baseDomain) {
+      errorCount = await new Promise(resolve => {
+        Services.clearData.deleteDataFromBaseDomain(
+          baseDomain,
+          true /* user request */,
+          Ci.nsIClearDataService.CLEAR_FORGET_ABOUT_SITE,
+          errorCode => resolve(bitCounting(errorCode))
+        );
+      });
+    } else {
+      // If we can't get a valid base domain for aDomainOrHost, fall back to
+      // delete by host.
+      errorCount = await new Promise(resolve => {
+        Services.clearData.deleteDataFromHost(
+          aDomainOrHost,
+          true /* user request */,
+          Ci.nsIClearDataService.CLEAR_FORGET_ABOUT_SITE,
+          errorCode => resolve(bitCounting(errorCode))
+        );
+      });
+    }
+
+    if (errorCount !== 0) {
+      throw new Error(
+        `There were a total of ${errorCount} errors during removal`
+      );
+    }
+  },
+
+  /**
+   * @deprecated This is a legacy method which clears by host only. Also it does
+   * not clear all storage partitioned via dFPI. Use removeDataFromBaseDomain
+   * instead.
+   */
+  async removeDataFromDomain(aDomain) {
+    let promises = [
+      new Promise(resolve =>
+        Services.clearData.deleteDataFromHost(
+          aDomain,
+          true /* user request */,
+          Ci.nsIClearDataService.CLEAR_FORGET_ABOUT_SITE,
+          errorCode => resolve(bitCounting(errorCode))
+        )
+      ),
+    ];
+
+    try {
+      let baseDomain = Services.eTLD.getBaseDomainFromHost(aDomain);
+
+      let cookies = Services.cookies.cookies;
+      let hosts = new Set();
+      for (let cookie of cookies) {
+        if (Services.eTLD.hasRootDomain(cookie.rawHost, baseDomain)) {
+          hosts.add(cookie.rawHost);
+        }
+      }
+
+      for (let host of hosts) {
+        promises.push(
+          new Promise(resolve =>
+            Services.clearData.deleteDataFromHost(
+              host,
+              true /* user request */,
+              Ci.nsIClearDataService.CLEAR_COOKIES,
+              errorCode => resolve(bitCounting(errorCode))
+            )
+          )
+        );
+      }
+    } catch (e) {
+      // - NS_ERROR_HOST_IS_IP_ADDRESS: the host is in ipv4/ipv6.
+      // - NS_ERROR_INSUFFICIENT_DOMAIN_LEVELS: not enough domain parts to extract,
+      //   i.e. the host is on the PSL.
+      // In both these cases we should probably not try to use the host as a base
+      // domain to remove more data, but we can still (try to) continue deleting the host.
+      if (
+        e.result != Cr.NS_ERROR_HOST_IS_IP_ADDRESS &&
+        e.result != Cr.NS_ERROR_INSUFFICIENT_DOMAIN_LEVELS
+      ) {
+        throw e;
+      }
+    }
+
+    let errorCount = (await Promise.all(promises)).reduce((a, b) => a + b);
+
+    if (errorCount !== 0) {
+      throw new Error(
+        `There were a total of ${errorCount} errors during removal`
+      );
+    }
+  },
+};
+
+function bitCounting(value) {
+  // To know more about how to count bits set to 1 in a numeric value, see this
+  // interesting article:
+  // https://blogs.msdn.microsoft.com/jeuge/2005/06/08/bit-fiddling-3/
+  const count =
+    value - ((value >> 1) & 0o33333333333) - ((value >> 2) & 0o11111111111);
+  return ((count + (count >> 3)) & 0o30707070707) % 63;
+}