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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "sync/internal_api/syncapi_internal.h"
      6 
      7 #include "base/memory/scoped_ptr.h"
      8 #include "sync/protocol/attachments.pb.h"
      9 #include "sync/protocol/password_specifics.pb.h"
     10 #include "sync/protocol/sync.pb.h"
     11 #include "sync/util/cryptographer.h"
     12 
     13 namespace syncer {
     14 
     15 namespace {
     16 
     17 bool EndsWithSpace(const std::string& string) {
     18   return !string.empty() && *string.rbegin() == ' ';
     19 }
     20 
     21 }
     22 
     23 sync_pb::PasswordSpecificsData* DecryptPasswordSpecifics(
     24     const sync_pb::EntitySpecifics& specifics, Cryptographer* crypto) {
     25   if (!specifics.has_password())
     26     return NULL;
     27   const sync_pb::PasswordSpecifics& password_specifics = specifics.password();
     28   if (!password_specifics.has_encrypted())
     29     return NULL;
     30   const sync_pb::EncryptedData& encrypted = password_specifics.encrypted();
     31   scoped_ptr<sync_pb::PasswordSpecificsData> data(
     32       new sync_pb::PasswordSpecificsData);
     33   if (!crypto->Decrypt(encrypted, data.get()))
     34     return NULL;
     35   return data.release();
     36 }
     37 
     38 // The list of names which are reserved for use by the server.
     39 static const char* kForbiddenServerNames[] = { "", ".", ".." };
     40 
     41 // When taking a name from the syncapi, append a space if it matches the
     42 // pattern of a server-illegal name followed by zero or more spaces.
     43 void SyncAPINameToServerName(const std::string& syncer_name,
     44                              std::string* out) {
     45   *out = syncer_name;
     46   if (IsNameServerIllegalAfterTrimming(*out))
     47     out->append(" ");
     48 }
     49 
     50 // In the reverse direction, if a server name matches the pattern of a
     51 // server-illegal name followed by one or more spaces, remove the trailing
     52 // space.
     53 void ServerNameToSyncAPIName(const std::string& server_name,
     54                              std::string* out) {
     55   CHECK(out);
     56   int length_to_copy = server_name.length();
     57   if (IsNameServerIllegalAfterTrimming(server_name) &&
     58       EndsWithSpace(server_name)) {
     59     --length_to_copy;
     60   }
     61   *out = server_name.substr(0, length_to_copy);
     62 }
     63 
     64 // Checks whether |name| is a server-illegal name followed by zero or more space
     65 // characters.  The three server-illegal names are the empty string, dot, and
     66 // dot-dot.  Very long names (>255 bytes in UTF-8 Normalization Form C) are
     67 // also illegal, but are not considered here.
     68 bool IsNameServerIllegalAfterTrimming(const std::string& name) {
     69   size_t untrimmed_count = name.find_last_not_of(' ') + 1;
     70   for (size_t i = 0; i < arraysize(kForbiddenServerNames); ++i) {
     71     if (name.compare(0, untrimmed_count, kForbiddenServerNames[i]) == 0)
     72       return true;
     73   }
     74   return false;
     75 }
     76 
     77 // Compare the values of two EntitySpecifics, accounting for encryption.
     78 bool AreSpecificsEqual(const Cryptographer* cryptographer,
     79                        const sync_pb::EntitySpecifics& left,
     80                        const sync_pb::EntitySpecifics& right) {
     81   // Note that we can't compare encrypted strings directly as they are seeded
     82   // with a random value.
     83   std::string left_plaintext, right_plaintext;
     84   if (left.has_encrypted()) {
     85     if (!cryptographer->CanDecrypt(left.encrypted())) {
     86       NOTREACHED() << "Attempting to compare undecryptable data.";
     87       return false;
     88     }
     89     left_plaintext = cryptographer->DecryptToString(left.encrypted());
     90   } else {
     91     left_plaintext = left.SerializeAsString();
     92   }
     93   if (right.has_encrypted()) {
     94     if (!cryptographer->CanDecrypt(right.encrypted())) {
     95       NOTREACHED() << "Attempting to compare undecryptable data.";
     96       return false;
     97     }
     98     right_plaintext = cryptographer->DecryptToString(right.encrypted());
     99   } else {
    100     right_plaintext = right.SerializeAsString();
    101   }
    102   if (left_plaintext == right_plaintext) {
    103     return true;
    104   }
    105   return false;
    106 }
    107 
    108 bool AreAttachmentMetadataEqual(const sync_pb::AttachmentMetadata& left,
    109                                 const sync_pb::AttachmentMetadata& right) {
    110   if (left.SerializeAsString() == right.SerializeAsString()) {
    111     return true;
    112   }
    113   return false;
    114 }
    115 
    116 }  // namespace syncer
    117