facilitate egistering dynamic content scripts with mappings data

2 files changed, 124 insertions, 1 deletions

diff --git a/background/broadcast_broker.js b/background/broadcast_broker.js
index 9847d7e..5af3a7b 100644
--- a/background/broadcast_broker.js
+++ b/background/broadcast_broker.js
@@ -141,7 +141,6 @@ function prepare_timeout_cb(sender_ctx, broadcast_data)
 
 function flush(sender_ctx)
 {
-    console.log('flushing', sender_ctx.prepared_broadcasts);
     sender_ctx.prepared_broadcasts.forEach(nv => broadcast(...nv));
     sender_ctx.prepared_broadcasts = new Set();
 }
diff --git a/background/patterns_query_manager.js b/background/patterns_query_manager.js
new file mode 100644
index 0000000..cb14cb1
--- /dev/null
+++ b/background/patterns_query_manager.js
@@ -0,0 +1,124 @@
+/**
+ * This file is part of Haketilo.
+ *
+ * Function: Instantiate the Pattern Tree data structure, filled with mappings
+ *           from IndexedDB.
+ *
+ * Copyright (C) 2021 Wojtek Kosior
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * As additional permission under GNU GPL version 3 section 7, you
+ * may distribute forms of that code without the copy of the GNU
+ * GPL normally required by section 4, provided you include this
+ * license notice and, in case of non-source distribution, a URL
+ * through which recipients can access the Corresponding Source.
+ * If you modify file(s) with this exception, you may extend this
+ * exception to your version of the file(s), but you are not
+ * obligated to do so. If you do not wish to do so, delete this
+ * exception statement from your version.
+ *
+ * As a special exception to the GPL, any HTML file which merely
+ * makes function calls to this code, and for that purpose
+ * includes it by reference shall be deemed a separate work for
+ * copyright law purposes. If you modify this code, you may extend
+ * this exception to your version of the code, but you are not
+ * obligated to do so. If you do not wish to do so, delete this
+ * exception statement from your version.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * I, Wojtek Kosior, thereby promise not to sue for violation of this file's
+ * license. Although I request that you do not make use this code in a
+ * proprietary program, I am not going to enforce this in court.
+ */
+
+#IMPORT common/patterns_query_tree.js  AS pqt
+#IMPORT common/indexeddb.js            AS haketilodb
+
+#FROM common/browser.js IMPORT browser
+
+const tree = pqt.make();
+#EXPORT tree
+
+const current_mappings = new Map();
+
+let registered_script = null;
+let script_update_occuring = false;
+let script_update_needed;
+
+async function update_content_script()
+{
+    if (script_update_occuring)
+	return;
+
+    script_update_occuring = true;
+
+    while (script_update_needed) {
+	script_update_needed = false;
+
+	const code = `\
+this.haketilo_pattern_tree = ${JSON.stringify(tree)};
+if (this.haketilo_content_script_main)
+    haketilo_content_script_main();`;
+
+	const new_script = await browser.contentScripts.register({
+	    "js": [{code}],
+	    "matches": ["<all_urls>"],
+	    "allFrames": true,
+	    "runAt": "document_start"
+	});
+
+	if (registered_script)
+	    registered_script.unregister();
+
+	registered_script = new_script;
+    }
+
+    script_update_occuring = false;
+}
+
+function register_mapping(mapping)
+{
+    for (const pattern in mapping.payloads)
+	pqt.register(tree, pattern, mapping.identifier, mapping);
+    current_mappings.set(mapping.identifier, mapping);
+}
+
+function mapping_changed(change)
+{
+    console.log('mapping changes!', arguments);
+    const old_version = current_mappings.get(change.identifier);
+    if (old_version !== undefined) {
+	for (const pattern in old_version.payloads)
+	    pqt.deregister(tree, pattern, change.identifier);
+
+	current_mappings.delete(change.identifier);
+    }
+
+    if (change.new_val !== undefined)
+	register_mapping(change.new_val);
+
+    script_update_needed = true;
+    setTimeout(update_content_script, 0);
+}
+
+async function start()
+{
+    const [tracking, initial_mappings] =
+	  await haketilodb.track_mappings(mapping_changed);
+
+    initial_mappings.forEach(register_mapping);
+    script_update_needed = true;
+    await update_content_script();
+}
+#EXPORT start