comparison index.cpp @ 460:17003dff8127 api-inversion

Convert index-finding logic to C functions.

New audiodb_index_exists() and audiodb_index_get_name().  The behaviours
of the functions are unchanged, even though they are kind of weird; in
particular, passing in a buffer rather than returning a char * for
audiodb_index_get_name() is probably likely to work better eventually
(see the changes to soap.cpp, which show a clear leak of a buffer in the
error case)

   adb_qstate_internal_t *qstate;
 } adb_qcallback_t;
 
 /************************* LSH indexing and query initialization  *****************/
 
-char* audioDB::index_get_name(const char*dbName, double radius, Uns32T sequenceLength){
-  char* indexName = new char[MAXSTR];  
-  // Attempt to make new file
-  if(strlen(dbName) > (MAXSTR - 32))
-    error("dbName is too long for LSH index filename appendages");
+/* FIXME: there are several things wrong with this: the memory
+ * discipline isn't ideal, the radius printing is a bit lame, the name
+ * getting will succeed or fail depending on whether the path was
+ * relative or absolute -- but most importantly encoding all that
+ * information in a filename is going to lose: it's impossible to
+ * maintain backwards-compatibility.  Instead we should probably store
+ * the index metadata inside the audiodb instance. */
+char *audiodb_index_get_name(const char *dbName, double radius, Uns32T sequenceLength) {
+  char *indexName;
+  if(strlen(dbName) > (MAXSTR - 32)) {
+    return NULL;
+  }
+  indexName = new char[MAXSTR];  
   strncpy(indexName, dbName, MAXSTR);
   sprintf(indexName+strlen(dbName), ".lsh.%019.9f.%d", radius, sequenceLength);
   return indexName;
 }
 
-// return true if index exists else return false
-int audioDB::index_exists(const char* dbName, double radius, Uns32T sequenceLength){
-  // Test to see if file exists
-  char* indexName = index_get_name(dbName, radius, sequenceLength);
-  lshfid = open (indexName, O_RDONLY);
-  delete[] indexName;
-  close(lshfid);
-  
-  if(lshfid<0)
-    return false;  
-  else
+bool audiodb_index_exists(const char *dbName, double radius, Uns32T sequenceLength) {
+  char *indexName = audiodb_index_get_name(dbName, radius, sequenceLength);
+  if(!indexName) {
+    return false;
+  }
+  struct stat st;
+  if(stat(indexName, &st)) {
+    delete [] indexName;
+    return false;
+  }
+  /* FIXME: other stat checks here? */
+  /* FIXME: is there any better way to check whether we can open a
+   * file for reading than by opening a file for reading? */
+  int fd = open(indexName, O_RDONLY);
+  delete [] indexName;
+  if(fd < 0) {
+    return false;
+  } else {
+    close(fd);
     return true;
+  }
 }
 
 // If we are a server and have a memory-resident index, check the indexName against the resident index (using get_indexName())
 // If they match, i.e. path+dbName_resident == path+dbName_requested, use
 // the memory-resident index.

     usingPower = true;
   
   if(dbH->flags & O2_FLAG_TIMES)
     usingTimes = true;
 
-  newIndexName = index_get_name(dbName, radius, sequenceLength);
+  newIndexName = audiodb_index_get_name(dbName, radius, sequenceLength);
+  if(!newIndexName) {
+    error("failed to get index name", dbName);
+  }
 
   // Set unit norming flag override
   audioDB::normalizedDistance = !audioDB::no_unit_norming;
 
   VERB_LOG(1, "INDEX: dim %d\n", (int)dbH->dim);

 
 
 // return true if indexed query performed else return false
 int audioDB::index_init_query(const char* dbName){
 
-  if(!(index_exists(dbName, radius, sequenceLength)))
+  if(!(audiodb_index_exists(dbName, radius, sequenceLength)))
     return false;
 
-  char* indexName = index_get_name(dbName, radius, sequenceLength);  
+  char *indexName = audiodb_index_get_name(dbName, radius, sequenceLength);
+  if(!indexName) {
+    error("failed to get index name", dbName);
+  }
 
   // Test to see if file exists
   if((lshfid = open (indexName, O_RDONLY)) < 0){
     delete[] indexName;
     return false;  

   }
 
   if(!index_init_query(adb->path)) // sets-up LSH index structures for querying
     return 0;
 
-  char* database = index_get_name(adb->path, radius, sequenceLength);
+  char *database = audiodb_index_get_name(adb->path, radius, sequenceLength);
+  if(!database) {
+    error("failed to get index name", adb->path);
+  }
 
   if(audiodb_query_spec_qpointers(adb, spec, &query_data, &query, &qpointers)) {
     error("failed to set up qpointers");
   }