[Sync] replacing base::hash_map/set with std::unordered_map/set.

BUG=567280

Review URL: https://codereview.chromium.org/1506743006

Cr-Commit-Position: refs/heads/master@{#366650}

3 files changed, 26 insertions, 51 deletions

diff --git a/sync/syncable/directory.cc b/sync/syncable/directory.cc
index 9c51f00..d81b861 100644
--- a/sync/syncable/directory.cc
+++ b/sync/syncable/directory.cc
@@ -776,49 +776,32 @@ bool Directory::PurgeEntriesWithTypeIn(ModelTypeSet disabled_types,
       if (!found_progress)
         return true;
 
-      // We iterate in two passes to avoid a bug in STLport (which is used in
-      // the Android build).  There are some versions of that library where a
-      // hash_map's iterators can be invalidated when an item is erased from the
-      // hash_map.
-      // See http://sourceforge.net/p/stlport/bugs/239/.
-
-      std::set<EntryKernel*> to_purge;
       for (MetahandlesMap::iterator it = kernel_->metahandles_map.begin();
-           it != kernel_->metahandles_map.end(); ++it) {
-        const sync_pb::EntitySpecifics& local_specifics =
-            it->second->ref(SPECIFICS);
+           it != kernel_->metahandles_map.end();) {
+        EntryKernel* entry = it->second;
+        const sync_pb::EntitySpecifics& local_specifics = entry->ref(SPECIFICS);
         const sync_pb::EntitySpecifics& server_specifics =
-            it->second->ref(SERVER_SPECIFICS);
+            entry->ref(SERVER_SPECIFICS);
         ModelType local_type = GetModelTypeFromSpecifics(local_specifics);
         ModelType server_type = GetModelTypeFromSpecifics(server_specifics);
 
+        // Increment the iterator before (potentially) calling DeleteEntry,
+        // otherwise our iterator may be invalidated.
+        ++it;
+
         if ((IsRealDataType(local_type) && disabled_types.Has(local_type)) ||
             (IsRealDataType(server_type) && disabled_types.Has(server_type))) {
-          to_purge.insert(it->second);
-        }
-      }
-
-      for (std::set<EntryKernel*>::iterator it = to_purge.begin();
-           it != to_purge.end(); ++it) {
-        EntryKernel* entry = *it;
-
-        const sync_pb::EntitySpecifics& local_specifics =
-            (*it)->ref(SPECIFICS);
-        const sync_pb::EntitySpecifics& server_specifics =
-            (*it)->ref(SERVER_SPECIFICS);
-        ModelType local_type = GetModelTypeFromSpecifics(local_specifics);
-        ModelType server_type = GetModelTypeFromSpecifics(server_specifics);
-
-        if (types_to_unapply.Has(local_type) ||
-            types_to_unapply.Has(server_type)) {
-          UnapplyEntry(entry);
-        } else {
-          bool save_to_journal =
-              (types_to_journal.Has(local_type) ||
-               types_to_journal.Has(server_type)) &&
-              (delete_journal_->IsDeleteJournalEnabled(local_type) ||
-               delete_journal_->IsDeleteJournalEnabled(server_type));
-          DeleteEntry(lock, save_to_journal, entry, &entries_to_journal);
+          if (types_to_unapply.Has(local_type) ||
+              types_to_unapply.Has(server_type)) {
+            UnapplyEntry(entry);
+          } else {
+            bool save_to_journal =
+                (types_to_journal.Has(local_type) ||
+                 types_to_journal.Has(server_type)) &&
+                (delete_journal_->IsDeleteJournalEnabled(local_type) ||
+                 delete_journal_->IsDeleteJournalEnabled(server_type));
+            DeleteEntry(lock, save_to_journal, entry, &entries_to_journal);
+          }
         }
       }
 
diff --git a/sync/syncable/directory.h b/sync/syncable/directory.h
index 06dbc5b..0884b42 100644
--- a/sync/syncable/directory.h
+++ b/sync/syncable/directory.h
@@ -11,6 +11,7 @@
 #include <deque>
 #include <set>
 #include <string>
+#include <unordered_map>
 #include <vector>
 
 #include "base/callback.h"
@@ -62,21 +63,11 @@ class SYNC_EXPORT Directory {
  public:
   typedef std::vector<int64_t> Metahandles;
 
-  // TODO(skym): Convert this hash_map usage to unordered_map, crbug/567280.
-  // Be careful when using these hash_map containers.  According to the spec,
-  // inserting into them may invalidate all iterators.
-  //
-  // It gets worse, though.  The Anroid STL library has a bug that means it may
-  // invalidate all iterators when you erase from the map, too.  That means that
-  // you can't iterate while erasing.  STLDeleteElements(), std::remove_if(),
-  // and other similar functions are off-limits too, until this bug is fixed.
-  //
-  // See http://sourceforge.net/p/stlport/bugs/239/.
-  typedef base::hash_map<int64_t, EntryKernel*> MetahandlesMap;
-  typedef base::hash_map<std::string, EntryKernel*> IdsMap;
-  typedef base::hash_map<std::string, EntryKernel*> TagsMap;
+  typedef std::unordered_map<int64_t, EntryKernel*> MetahandlesMap;
+  typedef std::unordered_map<std::string, EntryKernel*> IdsMap;
+  typedef std::unordered_map<std::string, EntryKernel*> TagsMap;
   typedef std::string AttachmentIdUniqueId;
-  typedef base::hash_map<AttachmentIdUniqueId, MetahandleSet>
+  typedef std::unordered_map<AttachmentIdUniqueId, MetahandleSet>
       IndexByAttachmentId;
 
   static const base::FilePath::CharType kSyncDatabaseFilename[];
diff --git a/sync/syncable/directory_backing_store.cc b/sync/syncable/directory_backing_store.cc
index 9272ae5..2ee31e9 100644
--- a/sync/syncable/directory_backing_store.cc
+++ b/sync/syncable/directory_backing_store.cc
@@ -8,6 +8,7 @@
 #include <stdint.h>
 
 #include <limits>
+#include <unordered_set>
 
 #include "base/base64.h"
 #include "base/logging.h"
@@ -1636,7 +1637,7 @@ bool DirectoryBackingStore::CreateShareInfoTableVersion71(
 bool DirectoryBackingStore::VerifyReferenceIntegrity(
     const Directory::MetahandlesMap* handles_map) {
   TRACE_EVENT0("sync", "SyncDatabaseIntegrityCheck");
-  typedef base::hash_set<std::string> IdsSet;
+  typedef std::unordered_set<std::string> IdsSet;
 
   IdsSet ids_set;
   bool is_ok = true;