Introduce UrlPattern.

chrome/common/extensions/url_pattern.h

Index: chrome/common/extensions/url_pattern.h
diff --git a/chrome/common/extensions/url_pattern.h b/chrome/common/extensions/url_pattern.h
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+// Copyright (c) 2006-2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+#ifndef CHROME_BROWSER_EXTENSIONS_MATCH_PATTERN_H_
+#define CHROME_BROWSER_EXTENSIONS_MATCH_PATTERN_H_
+
+#include "googleurl/src/gurl.h"
+
+// A pattern that can be used to match URLs. A URLPattern is a very restricted
+// subset of URL syntax:
+//
+// <url-pattern> := <scheme>://<host><path>
+// <scheme> := 'http' | 'https' | 'file' | 'ftp' | 'chrome-ui'
+// <host> := '*' | '*.' <anychar except '/' and '*'>+
+// <path> := '/' <any chars>
+//
+// * Host is not used when the scheme is 'file'.
+// * The path can have embedded '*' characters which act as glob wildcards.
+//
+// Examples of valid patterns:
+// - http://*/*
+// - http://*/foo*
+// - https://*.google.com/foo*bar
+// - chrome-ui://foo/bar
+// - file://monkey*
+// - http://127.0.0.1/*
+//
+// Examples of invalid patterns:
+// - http://* -- path not specified
+// - http://*foo/bar -- * not allowed as substring of host component
+// - http://foo.*.bar/baz -- * must be first component
+// - http:/bar -- scheme separator not found
+// - foo://* -- invalid scheme
+//
+// Design rationale:
+// * We need to be able to tell users what 'sites' a given URLPattern will
+//   affect. For example "This extension will interact with the site
+//   'www.google.com'.
+// * We'd like to be able to convert as many existing Greasemonkey @include
+//   patterns to URLPatterns as possible. Greasemonkey @include patterns are
+//   simple globs, so this won't be perfect.
+// * Although we would like to support any scheme, it isn't clear what to tell
+//   users about URLPatterns that affect data or javascript URLs, and saying
+//   something useful about chrome-extension URLs is more work, so those are
+//   left out for now.
+//
+// From a 2008-ish crawl of userscripts.org, the following patterns were found
+// in @include lines:
+// - total lines                    : 24271
+// - @include *                     :   919
+// - @include http://[^\*]+?/       : 11128 (no star in host)
+// - @include http://\*\.[^\*]+?/   :  2325 (host prefixed by *.)
+// - @include http://\*[^\.][^\*]+?/:  1524 (host prefixed by *, no dot -- many
+//                                           appear to only need subdomain
+//                                           matching, not real prefix matching)
+// - @include http://[^\*/]+\*/     :   320 (host suffixed by *)
+// - @include contains .tld         :   297 (host suffixed by .tld -- a special
+//                                           Greasemonkey domain component that
+//                                           tries to match all valid registry-
+//                                           controlled suffixes)
+// - @include http://\*/            :   228 (host is * exactly, but there is
+//                                           more to the pattern)
+//
+// So, we can support at least half of current @include lines without supporting
+// subdomain matching. We can pick up at least another 10% by supporting
+// subdomain matching. It is probably possible to coerce more of the existing
+// patterns to URLPattern, but the resulting pattern will be more restrictive
+// than the original glob, which is probably better than nothing.
+class URLPattern {
+ public:
+  URLPattern() : match_subdomains_(false) {}
+
+  // Initializes this instance by parsing the provided string. On failure, the
+  // instance will have some intermediate values and is in an invalid state.
+  bool Parse(const std::string& pattern_str);
+
+  // Returns true if this instance matches the specified URL.
+  bool MatchesUrl(const GURL& url);
+
+  // Get the scheme the pattern matches. This will always return a valid scheme
+  // if is_valid() returns true.
+  std::string scheme() const { return scheme_; }
+
+  // Gets the host the pattern matches. This can be an empty string if the
+  // pattern matches all hosts (the input was <scheme>://*/<whatever>).
+  std::string host() const { return host_; }
+
+  // Gets whether to match subdomains of host().
+  bool match_subdomains() const { return match_subdomains_; }
+
+  // Gets the path the pattern matches with the leading slash. This can have
+  // embedded asterisks which are interpreted using glob rules.
+  std::string path() const { return path_; }
+
+ private:
+  // Returns true if |test| matches our host.
+  bool MatchesHost(const GURL& test);
+
+  // Returns true if |test| matches our path.
+  bool MatchesPath(const GURL& test);
+
+  // The scheme for the pattern.
+  std::string scheme_;
+
+  // The host without any leading "*" components.
+  std::string host_;
+
+  // Whether we should match subdomains of the host. This is true if the first
+  // component of the pattern's host was "*".
+  bool match_subdomains_;
+
+  // The path to match. This is everything after the host of the URL, or
+  // everything after the scheme in the case of file:// URLs.
+  std::string path_;
+
+  // The path with "?" and "\" characters escaped for use with the
+  // MatchPattern() function. This is populated lazily, the first time it is
+  // needed.
+  std::string path_escaped_;
+};
+
+#endif CHROME_BROWSER_EXTENSIONS_MATCH_PATTERN_H_