Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 199 insertions, 0 deletions

diff --git a/toolkit/actors/ContentMetaChild.sys.mjs b/toolkit/actors/ContentMetaChild.sys.mjs
new file mode 100644
index 0000000000..929d92db47
--- /dev/null
+++ b/toolkit/actors/ContentMetaChild.sys.mjs
@@ -0,0 +1,199 @@
+/* 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/. */
+
+// Debounce time in milliseconds - this should be long enough to account for
+// sync script tags that could appear between desired meta tags
+const TIMEOUT_DELAY = 1000;
+
+const ACCEPTED_PROTOCOLS = ["http:", "https:"];
+
+// Possible description tags, listed in order from least favourable to most favourable
+const DESCRIPTION_RULES = [
+  "twitter:description",
+  "description",
+  "og:description",
+];
+
+// Possible image tags, listed in order from least favourable to most favourable
+const PREVIEW_IMAGE_RULES = [
+  "thumbnail",
+  "twitter:image",
+  "og:image",
+  "og:image:url",
+  "og:image:secure_url",
+];
+
+/*
+ * Checks if the incoming meta tag has a greater score than the current best
+ * score by checking the index of the meta tag in the list of rules provided.
+ *
+ * @param {Array} aRules
+ *          The list of rules for a given type of meta tag
+ * @param {String} aTag
+ *          The name or property of the incoming meta tag
+ * @param {String} aEntry
+ *          The current best entry for the given meta tag
+ *
+ * @returns {Boolean} true if the incoming meta tag is better than the current
+ *                    best meta tag of that same kind, false otherwise
+ */
+function shouldExtractMetadata(aRules, aTag, aEntry) {
+  return aRules.indexOf(aTag) > aEntry.currMaxScore;
+}
+
+/*
+ * Ensure that the preview image URL is safe and valid before storing
+ *
+ * @param {URL} aURL
+ *          A URL object that needs to be checked for valid principal and protocol
+ *
+ * @returns {Boolean} true if the preview URL is safe and can be stored, false otherwise
+ */
+function checkLoadURIStr(aURL) {
+  if (!ACCEPTED_PROTOCOLS.includes(aURL.protocol)) {
+    return false;
+  }
+  try {
+    let ssm = Services.scriptSecurityManager;
+    let principal = ssm.createNullPrincipal({});
+    ssm.checkLoadURIStrWithPrincipal(
+      principal,
+      aURL.href,
+      ssm.DISALLOW_INHERIT_PRINCIPAL
+    );
+  } catch (e) {
+    return false;
+  }
+  return true;
+}
+
+/*
+ * This listens to DOMMetaAdded events and collects relevant metadata about the
+ * meta tag received. Then, it sends the metadata gathered from the meta tags
+ * and the url of the page as it's payload to be inserted into moz_places.
+ */
+export class ContentMetaChild extends JSWindowActorChild {
+  constructor() {
+    super();
+
+    // Store a mapping of the best description and preview
+    // image collected so far for a given URL.
+    this.metaTags = new Map();
+  }
+
+  didDestroy() {
+    for (let entry of this.metaTags.values()) {
+      entry.timeout.cancel();
+    }
+  }
+
+  handleEvent(event) {
+    switch (event.type) {
+      case "DOMContentLoaded":
+        const metaTags = this.contentWindow.document.querySelectorAll("meta");
+        for (let metaTag of metaTags) {
+          this.onMetaTag(metaTag);
+        }
+        break;
+      case "DOMMetaAdded":
+        this.onMetaTag(event.originalTarget);
+        break;
+      default:
+    }
+  }
+
+  onMetaTag(metaTag) {
+    const window = metaTag.ownerGlobal;
+
+    // If there's no meta tag, ignore this. Also verify that the window
+    // matches just to be safe.
+    if (!metaTag || !metaTag.ownerDocument || window != this.contentWindow) {
+      return;
+    }
+
+    const url = metaTag.ownerDocument.documentURI;
+
+    let name = metaTag.name;
+    let prop = metaTag.getAttributeNS(null, "property");
+    if (!name && !prop) {
+      return;
+    }
+
+    let tag = name || prop;
+
+    const entry = this.metaTags.get(url) || {
+      description: { value: null, currMaxScore: -1 },
+      image: { value: null, currMaxScore: -1 },
+      timeout: null,
+    };
+
+    // Malformed meta tag - do not store it
+    const content = metaTag.getAttributeNS(null, "content");
+    if (!content) {
+      return;
+    }
+
+    if (shouldExtractMetadata(DESCRIPTION_RULES, tag, entry.description)) {
+      // Extract the description
+      entry.description.value = content;
+      entry.description.currMaxScore = DESCRIPTION_RULES.indexOf(tag);
+    } else if (shouldExtractMetadata(PREVIEW_IMAGE_RULES, tag, entry.image)) {
+      // Extract the preview image
+      let value;
+      try {
+        value = new URL(content, url);
+      } catch (e) {
+        return;
+      }
+      if (value && checkLoadURIStr(value)) {
+        entry.image.value = value.href;
+        entry.image.currMaxScore = PREVIEW_IMAGE_RULES.indexOf(tag);
+      }
+    } else {
+      // We don't care about other meta tags
+      return;
+    }
+
+    if (!this.metaTags.has(url)) {
+      this.metaTags.set(url, entry);
+    }
+
+    if (entry.timeout) {
+      entry.timeout.delay = TIMEOUT_DELAY;
+    } else {
+      // We want to debounce incoming meta tags until we're certain we have the
+      // best one for description and preview image, and only store that one
+      entry.timeout = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
+      entry.timeout.initWithCallback(
+        () => {
+          entry.timeout = null;
+          this.metaTags.delete(url);
+          // We try to cancel the timers when we get destroyed, but if
+          // there's a race, catch it:
+          if (!this.manager || this.manager.isClosed) {
+            return;
+          }
+
+          // Save description and preview image to moz_places
+          this.sendAsyncMessage("Meta:SetPageInfo", {
+            url,
+            description: entry.description.value,
+            previewImageURL: entry.image.value,
+          });
+
+          // Telemetry for recording the size of page metadata
+          let metadataSize = entry.description.value
+            ? entry.description.value.length
+            : 0;
+          metadataSize += entry.image.value ? entry.image.value.length : 0;
+          Services.telemetry
+            .getHistogramById("PAGE_METADATA_SIZE")
+            .add(metadataSize);
+        },
+        TIMEOUT_DELAY,
+        Ci.nsITimer.TYPE_ONE_SHOT
+      );
+    }
+  }
+}