Simple PMP reader to parse Picasa's metadata

webkit/fileapi/media/picasa/pmp_table_reader.cc

+// Copyright (c) 2013 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.
+
+#include "webkit/fileapi/media/picasa/pmp_table_reader.h"
+
+#include "base/file_util.h"
+#include "base/files/file_path.h"
+#include "base/logging.h"
+#include "webkit/fileapi/media/picasa/pmp_column_reader.h"
+#include "webkit/fileapi/media/picasa/pmp_constants.h"
+
+namespace fileapi {
+
+namespace {
+  COMPILE_ASSERT(sizeof(double) == 8, double_must_be_8_bytes_long);
+}
+
+using std::string;
+
+PmpTableReader::PmpTableReader() : column_readers_(), max_row_count_(0) {
+
+}
+
+PmpTableReader::~PmpTableReader() {
+  for (std::vector<PmpColumnReader*>::iterator it = column_readers_.begin();
+       it != column_readers_.end(); it++) {
+    delete *it;
+  }
+}
+
+bool PmpTableReader::ReadFromDisk(const string& table_name,
+                                  const base::FilePath& directory_path,
+                                  const std::vector<std::string>& columns) {
+  // Expect to read some columns, otherwise, no point in using this
+  DCHECK(!columns.empty());
+
+  // Directory must exist
+  if(!file_util::DirectoryExists(directory_path)) {
+    return false;
+  }
+
+  string table_prefix = table_name + "_";
+  string pmp_suffix = ".pmp";
+
+  // Look for the "%s_0".format(table_name_) file, indicating table existence
+  base::FilePath indicator_file = directory_path.Append(table_prefix + "0");
+
+  // Expect the indicator file to exist but not be a directory
+  if(!file_util::PathExists(indicator_file) ||
+     file_util::DirectoryExists(indicator_file)) {
+    return false;
+  }
+
+  // Construct the column readers
+  for (std::vector<std::string>::const_iterator it = columns.begin();
+       it != columns.end(); it++) {
+    base::FilePath colfile_path = directory_path.Append(
+        table_prefix + *it + pmp_suffix);
+
+    // Constructed on the heap due to PmpColumnReader disallowing
+    // copies and assignment.
+    PmpColumnReader* column_reader = new PmpColumnReader(*it);
+    column_readers_.push_back(column_reader);
+
+    uint32 rows_parsed;
+    bool column_read_success = column_reader->ReadFromDisk(&rows_parsed,
+                                                           colfile_path);
+
+    // If couldn't read this column, fail out
+    if(!column_read_success) {
+      return false;
+    }
+
+    if(rows_parsed > max_row_count_) {
+      max_row_count_ = rows_parsed;
+    }
+  }
+
+  return true;
+}
+
+uint32 PmpTableReader::Count() {
+  return max_row_count_;
+}
+
+}  // namespace fileapi