// _VerifyHashFunction
bool
Volume::_VerifyHashFunction(hash_function_t function)
{
bool result = true;
// iterate over the entries in the root dir until we find an entry, that
// doesn't falsify the hash function
DirEntryIterator iterator(fTree, fRootVNode->GetDirID(),
fRootVNode->GetObjectID(), DOT_DOT_OFFSET + 1);
DirItem item;
int32 index = 0;
while (iterator.GetNext(&item, &index) == B_OK) {
DirEntry *entry = item.EntryAt(index);
uint64 offset = entry->GetOffset();
// try the hash function
size_t nameLen = 0;
if (const char *name = item.EntryNameAt(index, &nameLen)) {
uint64 testOffset = key_offset_for_name(function, name, nameLen);
if (offset_hash_value(offset) != offset_hash_value(testOffset)) {
result = false;
break;
}
} // else: bad data
}
return result;
}
/*! \brief Searches an entry in a directory.
\note Must not be called with \a entryName "." or ".."!
\param dir The directory.
\param entryName Name of the entry.
\param foundNode pointer to a pre-allocated VNode to be initialized to
the found entry.
\param failIfHidden The method shall fail, if the entry is hidden.
\return \c B_OK, if everything went fine.
*/
status_t
Volume::FindDirEntry(VNode *dir, const char *entryName, VNode *foundNode,
bool failIfHidden)
{
status_t error = (dir && foundNode ? B_OK : B_BAD_VALUE);
// find the DirEntry
DirItem item;
int32 entryIndex = 0;
if (error == B_OK) {
error = fTree->FindDirEntry(dir->GetDirID(), dir->GetObjectID(),
entryName, &item, &entryIndex);
}
// find the child node
if (error == B_OK) {
DirEntry *entry = item.EntryAt(entryIndex);
error = FindVNode(entry->GetDirID(), entry->GetObjectID(), foundNode);
if (error == B_OK && failIfHidden && entry->IsHidden())
error = B_ENTRY_NOT_FOUND;
}
return error;
}
// _DetectHashFunction
uint32
Volume::_DetectHashFunction()
{
// iterate over the entries in the root dir until we find an entry, that
// let us draw an unambiguous conclusion
DirEntryIterator iterator(fTree, fRootVNode->GetDirID(),
fRootVNode->GetObjectID(), DOT_DOT_OFFSET + 1);
uint32 foundCode = UNSET_HASH;
DirItem item;
int32 index = 0;
while (foundCode == UNSET_HASH
&& iterator.GetNext(&item, &index) == B_OK) {
DirEntry *entry = item.EntryAt(index);
uint64 offset = entry->GetOffset();
uint32 hashCodes[] = { TEA_HASH, YURA_HASH, R5_HASH };
int32 hashCodeCount = sizeof(hashCodes) / sizeof(uint32);
size_t nameLen = 0;
const char *name = item.EntryNameAt(index, &nameLen);
if (!name) // bad data!
continue;
// try each hash function -- if there's a single winner, we're done,
// otherwise the next entry must help
for (int32 i = 0; i < hashCodeCount; i++) {
hash_function_t function = hash_function_for_code(hashCodes[i]);
uint64 testOffset = key_offset_for_name(function, name, nameLen);
if (offset_hash_value(offset) == offset_hash_value(testOffset)) {
if (foundCode != UNSET_HASH) {
// ambiguous
foundCode = UNSET_HASH;
break;
} else
foundCode = hashCodes[i];
}
}
}
return foundCode;
}
/*! \brief Finds the node identified by a directory ID, object ID pair.
\note The method does not initialize the parent ID for non-directory nodes.
\param dirID Directory ID of the node to be found.
\param objectID Object ID of the node to be found.
\param node pointer to a pre-allocated VNode to be initialized to
the found node.
\return \c B_OK, if everything went fine.
*/
status_t
Volume::FindVNode(uint32 dirID, uint32 objectID, VNode *node)
{
// NOTE: The node's parent dir ID is not initialized!
status_t error = (node ? B_OK : B_BAD_VALUE);
// init the node
if (error == B_OK)
error = node->SetTo(dirID, objectID);
// find the stat item
StatItem item;
if (error == B_OK) {
error = fTree->FindStatItem(dirID, objectID, &item);
if (error != B_OK) {
FATAL(("Couldn't find stat item for node (%lu, %lu)\n",
dirID, objectID));
}
}
// get the stat data
if (error == B_OK)
SET_ERROR(error, item.GetStatData(node->GetStatData(), true));
// for dirs get the ".." entry, since we need the parent dir ID
if (error == B_OK && node->IsDir()) {
DirItem dirItem;
int32 index = 0;
error = fTree->FindDirEntry(dirID, objectID, "..", &dirItem, &index);
if (error == B_OK) {
DirEntry *entry = dirItem.EntryAt(index);
node->SetParentID(entry->GetDirID(), entry->GetObjectID());
}
else {
FATAL(("failed to find `..' entry for dir node (%lu, %ld)\n",
dirID, objectID));
}
}
return error;
}
