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-rw-r--r--common/patterns.js29
-rw-r--r--common/patterns_query_tree.js271
2 files changed, 289 insertions, 11 deletions
diff --git a/common/patterns.js b/common/patterns.js
index 635b128..054e610 100644
--- a/common/patterns.js
+++ b/common/patterns.js
@@ -17,16 +17,25 @@ const MAX = {
const proto_regex = /^(\w+):\/\/(.*)$/;
const user_re = "[^/?#@]+@"
-const domain_re = "[.a-zA-Z0-9-]+";
+const domain_re = "[.*a-zA-Z0-9-]+";
const path_re = "[^?#]*";
const query_re = "\\??[^#]*";
const http_regex = new RegExp(`^(${domain_re})(${path_re})(${query_re}).*`);
-const file_regex = new RegExp(`^(${path_re}).*`);
+const file_regex = new RegExp(`^(/${path_re}).*`);
const ftp_regex = new RegExp(`^(${user_re})?(${domain_re})(${path_re}).*`);
+function match_or_throw(regex, string, error_msg)
+{
+ const match = regex.exec(string);
+ if (match === null)
+ throw error_msg;
+
+ return match;
+}
+
function deconstruct_url(url, use_limits=true)
{
const max = MAX;
@@ -35,21 +44,19 @@ function deconstruct_url(url, use_limits=true)
max[key] = Infinity;
}
- const proto_match = proto_regex.exec(url);
- if (proto_match === null)
- throw `bad url '${url}'`;
+ const matcher = (re, str) => match_or_throw(re, str, `bad url '${url}'`)
+ const proto_match = matcher(proto_regex, url);
const deco = {proto: proto_match[1]};
if (deco.proto === "file") {
- deco.path = file_regex.exec(proto_match[2])[1];
+ deco.path = matcher(file_regex, proto_match[2])[1];
} else if (deco.proto === "ftp") {
- [deco.domain, deco.path] = ftp_regex.exec(proto_match[2]).slice(2, 4);
+ [deco.domain, deco.path] =
+ matcher(ftp_regex, proto_match[2]).slice(2, 4);
} else if (deco.proto === "http" || deco.proto === "https") {
- const http_match = http_regex.exec(proto_match[2]);
- if (!http_match)
- return undefined;
- [deco.domain, deco.path, deco.query] = http_match.slice(1, 4);
+ [deco.domain, deco.path, deco.query] =
+ matcher(http_regex, proto_match[2]).slice(1, 4);
deco.domain = deco.domain.toLowerCase();
} else {
throw `unsupported protocol in url '${url}'`;
diff --git a/common/patterns_query_tree.js b/common/patterns_query_tree.js
new file mode 100644
index 0000000..326c7b7
--- /dev/null
+++ b/common/patterns_query_tree.js
@@ -0,0 +1,271 @@
+/**
+ * This file is part of Haketilo.
+ *
+ * Function: Data structure to query items by URL patterns.
+ *
+ * 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.
+ */
+
+/*
+ * IMPORTS_START
+ * IMPORT deconstruct_url
+ * IMPORTS_END
+ */
+
+/*
+ * This is a javascript rewrite of Python implementation of the algorithm here:
+ * https://git.koszko.org/pydrilla/tree/src/pydrilla/pydrilla.py?id=f4edcbe7f4739d6f82a2e1bb180960b003b30862#n205
+ */
+
+/* "Pattern Tree" is how we refer to the data structure used for querying
+ * Haketilo patterns. Those look like 'https://*.example.com/ab/***'. The goal
+ * is to make it possible for given URL to quickly retrieve all known patterns
+ * that match it.
+ */
+function make_tree_node() {
+ return {
+ wildcard_matches: [null, null, null],
+ literal_match: null,
+ children: {}
+ };
+}
+
+function is_empty_node(tree_node) {
+ const children = tree_node.children;
+ for (const key in children) {
+ if (children.hasOwnProperty(key))
+ return false;
+ }
+
+ if (Array.reduce(tree_node.wildcard_matches, (a, b) => b && a !== null, 1))
+ return false;
+
+ return tree_node.literal_match === null;
+}
+
+const is_wildcard = segment => ["*", "**", "***"].lastIndexOf(segment) >= 0;
+
+/*
+ * Yields all matches of this segments sequence against the tree that starts at
+ * this node. Results are produces in order from greatest to lowest pattern
+ * specificity.
+ */
+function* search_sequence(tree_node, segments)
+{
+ const nodes = [tree_node];
+
+ for (const segment of segments) {
+ const next_node = nodes[nodes.length - 1].children[segment];
+ if (next_node === undefined)
+ break;
+
+ nodes.push(next_node);
+ }
+
+ const nsegments = segments.length;
+
+ const conds = [
+ /* literal pattern match */
+ () => nodes.length == nsegments,
+ /* wildcard pattern matches */
+ () => nodes.length + 1 == nsegments && segments[nsegments - 1] != "*",
+ () => nodes.length + 1 < nsegments,
+ () => nodes.length + 1 != nsegments || segments[nsegments - 1] != "***"
+ ];
+
+ while (nodes.length) {
+ const node = nodes.pop();
+ const items = [node.literal_match, ...node.wildcard_matches];
+
+ for (let i = 0; i < 4; i++) {
+ if (items[i] !== null && conds[i]())
+ yield items[i];
+ }
+ }
+}
+
+/*
+ * Make item queryable through (this branch of) the Pattern Tree or remove its
+ * path from there.
+ *
+ * item_modifier should be a function that accepts 1 argument, the item stored
+ * in the tree (or `null` if there wasn't any item there), and returns an item
+ * that should be used in place of the first one. It is also legal for it to
+ * return the same item modifying it first. If it returns `null`, it means the
+ * item should be deleted from the Tree.
+ *
+ * If there was not yet any item associated with the tree path designated by
+ * segments and value returned by item_modifier is not `null`, make the value
+ * queryable by this path.
+ */
+function modify_sequence(tree_node, segments, item_modifier)
+{
+ const nodes = [tree_node];
+ let removed = true;
+
+ for (var current_segment of segments) {
+ wildcards = tree_node.wildcard_matches;
+
+ const child = tree_node.children[current_segment] || make_tree_node();
+ tree_node.children[current_segment] = child;
+ tree_node = child;
+ nodes.push(tree_node);
+ }
+
+ tree_node.literal_match = item_modifier(tree_node.literal_match);
+ if (tree_node.literal_match !== null)
+ removed = false;
+
+ let i = segments.length;
+
+ if (is_wildcard(current_segment)) {
+ const asterisks = current_segment.length - 1;
+ const wildcards = nodes[i - 1].wildcard_matches;
+ wildcards[asterisks] = item_modifier(wildcards[asterisks]);
+ if (wildcards[asterisks] !== null)
+ removed = false;
+ }
+
+ while (!removed)
+ return;
+
+ while (i > 0) {
+ tree_node = nodes[i--];
+ if (is_empty_node(tree_node))
+ delete nodes[i].children[segments[i]];
+ }
+}
+
+/*
+ * Make item queryable through the Pattern Tree that starts with the protocols
+ * dictionary object passed in the first argument.
+ */
+function pattern_tree_register(patterns_by_proto, pattern, item_name, item)
+{
+ /*
+ * We pass 'false' to disable length limits on URL parts. Length limits are
+ * mostly useful in case of iteration over all patterns matching given URL.
+ * Here we don't do that.
+ */
+ const deco = deconstruct_url(pattern, false);
+
+ const tree = patterns_by_proto[deco.proto] || make_tree_node();
+ patterns_by_proto[deco.proto] = tree;
+
+ let path_trees;
+
+ if (deco.proto === "file") {
+ path_trees = [tree];
+ } else {
+ /* We need an aray of domain labels ordered most-significant-first. */
+ const domain = [...deco.domain].reverse();
+ path_trees = add_sequence(tree, domain, make_tree_node);
+ }
+
+ for (const path_tree of path_trees) {
+ for (const match_obj of add_sequence(path_tree, deco.path, () => {}))
+ match_obj[item_name] = item;
+ }
+}
+
+// /*
+// * Remove registered item from the Pattern Tree that starts with the protocols
+// * dictionary object passed in the first argument. The remaining 2 arguments
+// * should be pattern and name that have been earlier passed to
+// * pattern_tree_register().
+// */
+// function pattern_tree_deregister(patterns_by_proto, pattern, item_name)
+// {
+// const deco = deconstruct_url(pattern, false);
+
+// const tree = patterns_by_proto[deco.proto] || make_tree_node();
+// patterns_by_proto[deco.proto] = tree;
+
+// let path_trees;
+
+// if (deco.proto === "file") {
+// path_trees = [tree];
+// } else {
+// /* We need an aray of domain labels ordered most-significant-first. */
+// const domain = [...deco.domain].reverse();
+// ..........................
+// path_trees = add_sequence(tree, domain, make_tree_node);
+// }
+// }
+
+/*
+ * Yield registered items (as [item_name, item] arrays) that match url. For
+ * cosistent behavior, please don't modify the pattern tree while iterating over
+ * the results.
+ */
+function* pattern_tree_search(patterns_by_proto, url)
+{
+ const deco = deconstruct_url(url, false);
+
+ tree = patterns_by_proto[deco.proto] || make_tree_node();
+
+ let path_trees;
+
+ if (deco.proto === "file") {
+ path_trees = [tree];
+ } else {
+ /* We need an aray of domain labels ordered most-significant-first. */
+ const domain = [...deco.domain].reverse();
+ path_trees = search_sequence(tree, domain);
+ }
+
+ for (const path_tree of path_trees) {
+ for (const match_obj of search_sequence(path_tree, deco.path)) {
+ for (const entry of Object.entries(match_obj))
+ yield entry;
+ }
+ }
+}
+
+const pattern_tree = {
+ make: () => {},
+ register: pattern_tree_register,
+ // deregister: pattern_tree_deregister,
+ search: pattern_tree_search
+}
+
+/*
+ * EXPORTS_START
+ * EXPORT pattern_tree
+ * EXPORTS_END
+ */