Factor out the string lookup code from registry_controlled_domains

net/base/lookup_string_in_fixed_set.cc

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Copyright 2015 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.
 
-// NB: Modelled after Mozilla's code (originally written by Pamela Greene,
-// later modified by others), but almost entirely rewritten for Chrome.
-//   (netwerk/dns/src/nsEffectiveTLDService.cpp)
-/* ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1/GPL 2.0/LGPL 2.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- * http://www.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is Mozilla Effective-TLD Service
- *
- * The Initial Developer of the Original Code is
- * Google Inc.
- * Portions created by the Initial Developer are Copyright (C) 2006
- * the Initial Developer. All Rights Reserved.
- *
- * Contributor(s):
- *   Pamela Greene <pamg.bugs@gmail.com> (original author)
- *   Daniel Witte <dwitte@stanford.edu>
- *
- * Alternatively, the contents of this file may be used under the terms of
- * either the GNU General Public License Version 2 or later (the "GPL"), or
- * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
- * in which case the provisions of the GPL or the LGPL are applicable instead
- * of those above. If you wish to allow use of your version of this file only
- * under the terms of either the GPL or the LGPL, and not to allow others to
- * use your version of this file under the terms of the MPL, indicate your
- * decision by deleting the provisions above and replace them with the notice
- * and other provisions required by the GPL or the LGPL. If you do not delete
- * the provisions above, a recipient may use your version of this file under
- * the terms of any one of the MPL, the GPL or the LGPL.
- *
- * ***** END LICENSE BLOCK ***** */
-
-#include "net/base/registry_controlled_domains/registry_controlled_domain.h"
+#include "net/base/lookup_string_in_fixed_set.h"
 
 #include "base/logging.h"
-#include "base/strings/string_util.h"
-#include "base/strings/utf_string_conversions.h"
-#include "net/base/net_module.h"
-#include "net/base/net_util.h"
-#include "url/gurl.h"
-#include "url/third_party/mozilla/url_parse.h"
 
 namespace net {
-namespace registry_controlled_domains {
 
 namespace {
-#include "net/base/registry_controlled_domains/effective_tld_names-inc.cc"
-
-// See make_dafsa.py for documentation of the generated dafsa byte array.
-
-const unsigned char* g_graph = kDafsa;
-size_t g_graph_length = sizeof(kDafsa);
-
-const int kNotFound = -1;
-const int kExceptionRule = 1;
-const int kWildcardRule = 2;
-const int kPrivateRule = 4;
 
 // Read next offset from pos.
 // Returns true if an offset could be read, false otherwise.
-bool GetNextOffset(const unsigned char** pos, const unsigned char* end,
+bool GetNextOffset(const unsigned char** pos,
+                   const unsigned char* end,
                    const unsigned char** offset) {
   if (*pos == end)
     return false;
 
   // When reading an offset the byte array must always contain at least
   // three more bytes to consume. First the offset to read, then a node
   // to skip over and finally a destination node. No object can be smaller
   // than one byte.
   CHECK_LT(*pos + 2, end);
   size_t bytes_consumed;
@@ skipping 19 matching lines @@
 }
 
 // Check if byte at offset is last in label.
 bool IsEOL(const unsigned char* offset, const unsigned char* end) {
   CHECK_LT(offset, end);
   return (*offset & 0x80) != 0;
 }
 
 // Check if byte at offset matches first character in key.
 // This version matches characters not last in label.
-bool IsMatch(const unsigned char* offset, const unsigned char* end,
+bool IsMatch(const unsigned char* offset,
+             const unsigned char* end,
              const char* key) {
   CHECK_LT(offset, end);
   return *offset == *key;
 }
 
 // Check if byte at offset matches first character in key.
 // This version matches characters last in label.
-bool IsEndCharMatch(const unsigned char* offset, const unsigned char* end,
+bool IsEndCharMatch(const unsigned char* offset,
+                    const unsigned char* end,
                     const char* key) {
   CHECK_LT(offset, end);
   return *offset == (*key | 0x80);
 }
 
 // Read return value at offset.
 // Returns true if a return value could be read, false otherwise.
-bool GetReturnValue(const unsigned char* offset, const unsigned char* end,
+bool GetReturnValue(const unsigned char* offset,
+                    const unsigned char* end,
                     int* return_value) {
   CHECK_LT(offset, end);
   if ((*offset & 0xE0) == 0x80) {
     *return_value = *offset & 0x0F;
     return true;
   }
   return false;
 }
 
+}  // namespace
+
 // Lookup a domain key in a byte array generated by make_dafsa.py.
-// The rule type is returned if key is found, otherwise kNotFound is returned.
-int LookupString(const unsigned char* graph, size_t length, const char* key,
-                 size_t key_length) {
+// The rule type is returned if key is found, otherwise kDafsaNotFound is
+// returned.
+int LookupStringInFixedSet(const unsigned char* graph,
+                           size_t length,
+                           const char* key,
+                           size_t key_length) {
   const unsigned char* pos = graph;
   const unsigned char* end = graph + length;
   const unsigned char* offset = pos;
   const char* key_end = key + key_length;
   while (GetNextOffset(&pos, end, &offset)) {
     //   char <char>+ end_char offsets
     //   char <char>+ return value
     //   char end_char offsets
     //   char return value
     //   end_char offsets
     //   return_value
     bool did_consume = false;
     if (key != key_end && !IsEOL(offset, end)) {
       // Leading <char> is not a match. Don't dive into this child
       if (!IsMatch(offset, end, key))
         continue;
       did_consume = true;
       ++offset;
       ++key;
       // Possible matches at this point:
       // <char>+ end_char offsets
       // <char>+ return value
       // end_char offsets
       // return value
       // Remove all remaining <char> nodes possible
       while (!IsEOL(offset, end) && key != key_end) {
         if (!IsMatch(offset, end, key))
-          return kNotFound;
+          return kDafsaNotFound;
         ++key;
         ++offset;
       }
     }
     // Possible matches at this point:
     // end_char offsets
     // return_value
     // If one or more <char> elements were consumed, a failure
     // to match is terminal. Otherwise, try the next node.
     if (key == key_end) {
       int return_value;
       if (GetReturnValue(offset, end, &return_value))
         return return_value;
       // The DAFSA guarantees that if the first char is a match, all
       // remaining char elements MUST match if the key is truly present.
       if (did_consume)
-        return kNotFound;
+        return kDafsaNotFound;
       continue;
     }
     if (!IsEndCharMatch(offset, end, key)) {
       if (did_consume)
-        return kNotFound;  // Unexpected
+        return kDafsaNotFound;  // Unexpected
       continue;
     }
     ++key;
     pos = ++offset;  // Dive into child
   }
-  return kNotFound;  // No match
+  return kDafsaNotFound;  // No match
 }
 
-size_t GetRegistryLengthImpl(
-    const std::string& host,
-    UnknownRegistryFilter unknown_filter,
-    PrivateRegistryFilter private_filter) {
-  DCHECK(!host.empty());
-
-  // Skip leading dots.
-  const size_t host_check_begin = host.find_first_not_of('.');
-  if (host_check_begin == std::string::npos)
-    return 0;  // Host is only dots.
-
-  // A single trailing dot isn't relevant in this determination, but does need
-  // to be included in the final returned length.
-  size_t host_check_len = host.length();
-  if (host[host_check_len - 1] == '.') {
-    --host_check_len;
-    DCHECK(host_check_len > 0);  // If this weren't true, the host would be ".",
-                                 // and we'd have already returned above.
-    if (host[host_check_len - 1] == '.')
-      return 0;  // Multiple trailing dots.
-  }
-
-  // Walk up the domain tree, most specific to least specific,
-  // looking for matches at each level.
-  size_t prev_start = std::string::npos;
-  size_t curr_start = host_check_begin;
-  size_t next_dot = host.find('.', curr_start);
-  if (next_dot >= host_check_len)  // Catches std::string::npos as well.
-    return 0;  // This can't have a registry + domain.
-  while (1) {
-    const char* domain_str = host.data() + curr_start;
-    size_t domain_length = host_check_len - curr_start;
-    int type = LookupString(g_graph, g_graph_length, domain_str, domain_length);
-    bool do_check =
-        type != kNotFound && (!(type & kPrivateRule) ||
-                              private_filter == INCLUDE_PRIVATE_REGISTRIES);
-
-    // If the apparent match is a private registry and we're not including
-    // those, it can't be an actual match.
-    if (do_check) {
-      // Exception rules override wildcard rules when the domain is an exact
-      // match, but wildcards take precedence when there's a subdomain.
-      if (type & kWildcardRule && (prev_start != std::string::npos)) {
-        // If prev_start == host_check_begin, then the host is the registry
-        // itself, so return 0.
-        return (prev_start == host_check_begin) ? 0
-                                                : (host.length() - prev_start);
-      }
-
-      if (type & kExceptionRule) {
-        if (next_dot == std::string::npos) {
-          // If we get here, we had an exception rule with no dots (e.g.
-          // "!foo").  This would only be valid if we had a corresponding
-          // wildcard rule, which would have to be "*".  But we explicitly
-          // disallow that case, so this kind of rule is invalid.
-          NOTREACHED() << "Invalid exception rule";
-          return 0;
-        }
-        return host.length() - next_dot - 1;
-      }
-
-      // If curr_start == host_check_begin, then the host is the registry
-      // itself, so return 0.
-      return (curr_start == host_check_begin) ? 0
-                                              : (host.length() - curr_start);
-    }
-
-    if (next_dot >= host_check_len)  // Catches std::string::npos as well.
-      break;
-
-    prev_start = curr_start;
-    curr_start = next_dot + 1;
-    next_dot = host.find('.', curr_start);
-  }
-
-  // No rule found in the registry.  curr_start now points to the first
-  // character of the last subcomponent of the host, so if we allow unknown
-  // registries, return the length of this subcomponent.
-  return unknown_filter == INCLUDE_UNKNOWN_REGISTRIES ?
-      (host.length() - curr_start) : 0;
-}
-
-std::string GetDomainAndRegistryImpl(
-    const std::string& host, PrivateRegistryFilter private_filter) {
-  DCHECK(!host.empty());
-
-  // Find the length of the registry for this host.
-  const size_t registry_length =
-      GetRegistryLengthImpl(host, INCLUDE_UNKNOWN_REGISTRIES, private_filter);
-  if ((registry_length == std::string::npos) || (registry_length == 0))
-    return std::string();  // No registry.
-  // The "2" in this next line is 1 for the dot, plus a 1-char minimum preceding
-  // subcomponent length.
-  DCHECK(host.length() >= 2);
-  if (registry_length > (host.length() - 2)) {
-    NOTREACHED() <<
-        "Host does not have at least one subcomponent before registry!";
-    return std::string();
-  }
-
-  // Move past the dot preceding the registry, and search for the next previous
-  // dot.  Return the host from after that dot, or the whole host when there is
-  // no dot.
-  const size_t dot = host.rfind('.', host.length() - registry_length - 2);
-  if (dot == std::string::npos)
-    return host;
-  return host.substr(dot + 1);
-}
-
-}  // namespace
-
-std::string GetDomainAndRegistry(
-    const GURL& gurl,
-    PrivateRegistryFilter filter) {
-  const url::Component host = gurl.parsed_for_possibly_invalid_spec().host;
-  if ((host.len <= 0) || gurl.HostIsIPAddress())
-    return std::string();
-  return GetDomainAndRegistryImpl(std::string(
-      gurl.possibly_invalid_spec().data() + host.begin, host.len), filter);
-}
-
-std::string GetDomainAndRegistry(
-    const std::string& host,
-    PrivateRegistryFilter filter) {
-  url::CanonHostInfo host_info;
-  const std::string canon_host(CanonicalizeHost(host, &host_info));
-  if (canon_host.empty() || host_info.IsIPAddress())
-    return std::string();
-  return GetDomainAndRegistryImpl(canon_host, filter);
-}
-
-bool SameDomainOrHost(
-    const GURL& gurl1,
-    const GURL& gurl2,
-    PrivateRegistryFilter filter) {
-  // See if both URLs have a known domain + registry, and those values are the
-  // same.
-  const std::string domain1(GetDomainAndRegistry(gurl1, filter));
-  const std::string domain2(GetDomainAndRegistry(gurl2, filter));
-  if (!domain1.empty() || !domain2.empty())
-    return domain1 == domain2;
-
-  // No domains.  See if the hosts are identical.
-  const url::Component host1 = gurl1.parsed_for_possibly_invalid_spec().host;
-  const url::Component host2 = gurl2.parsed_for_possibly_invalid_spec().host;
-  if ((host1.len <= 0) || (host1.len != host2.len))
-    return false;
-  return !strncmp(gurl1.possibly_invalid_spec().data() + host1.begin,
-                  gurl2.possibly_invalid_spec().data() + host2.begin,
-                  host1.len);
-}
-
-size_t GetRegistryLength(
-    const GURL& gurl,
-    UnknownRegistryFilter unknown_filter,
-    PrivateRegistryFilter private_filter) {
-  const url::Component host = gurl.parsed_for_possibly_invalid_spec().host;
-  if (host.len <= 0)
-    return std::string::npos;
-  if (gurl.HostIsIPAddress())
-    return 0;
-  return GetRegistryLengthImpl(
-      std::string(gurl.possibly_invalid_spec().data() + host.begin, host.len),
-      unknown_filter,
-      private_filter);
-}
-
-size_t GetRegistryLength(
-    const std::string& host,
-    UnknownRegistryFilter unknown_filter,
-    PrivateRegistryFilter private_filter) {
-  url::CanonHostInfo host_info;
-  const std::string canon_host(CanonicalizeHost(host, &host_info));
-  if (canon_host.empty())
-    return std::string::npos;
-  if (host_info.IsIPAddress())
-    return 0;
-  return GetRegistryLengthImpl(canon_host, unknown_filter, private_filter);
-}
-
-void SetFindDomainGraph() {
-  g_graph = kDafsa;
-  g_graph_length = sizeof(kDafsa);
-}
-
-void SetFindDomainGraph(const unsigned char* domains, size_t length) {
-  CHECK(domains);
-  CHECK_NE(length, 0u);
-  g_graph = domains;
-  g_graph_length = length;
-}
-
-}  // namespace registry_controlled_domains
 }  // namespace net