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.

[vandebo (ex-Chrome), 2013/03/29 21:35:07]

nit: no (c)

[tommycli, 2013/04/01 22:19:18]

Done.

+// 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 <algorithm>
+
+#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);
+
+}  // namespace
+
+PmpTableReader::PmpTableReader() : column_readers_(), max_row_count_(0) { }
+
+PmpTableReader::~PmpTableReader() { }
+
+bool PmpTableReader::InitFromDisk(const std::string& table_name,
+                                  const base::FilePath& directory_path,
+                                  const std::vector<std::string>& columns) {
+  // Expect to read some columns, otherwise, a programming error.

[vandebo (ex-Chrome), 2013/03/29 21:35:07]

Remove comment.

[tommycli, 2013/04/01 22:19:18]

Done.

+  DCHECK(!columns.empty());
+
+  // Only allow initialization once

[vandebo (ex-Chrome), 2013/03/29 21:35:07]

Remove comment.

[tommycli, 2013/04/01 22:19:18]

Done.

+  if(!column_readers_.empty())
+    return false;
+
+  // Directory must exist.

[vandebo (ex-Chrome), 2013/03/29 21:35:07]

Remove comment.

[tommycli, 2013/04/01 22:19:18]

Done.

+  if(!file_util::DirectoryExists(directory_path))
+    return false;
+
+  std::string table_prefix = table_name + "_";
+
+  // Look for the "%s_0".format(table_name_) file, indicating table existence.

[vandebo (ex-Chrome), 2013/03/29 21:35:07]

Does '"%s_0".format(table_name_)' mean table_name_ + "_0" ?  If so, say that.

[tommycli, 2013/04/01 22:19:18]

Done.

+  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;
+  }
+
+  ScopedVector<PmpColumnReader> column_readers;
+  uint32 max_row_count = 0;
+
+  // Construct the column readers.

[vandebo (ex-Chrome), 2013/03/29 21:35:07]

Remove comment.

[tommycli, 2013/04/01 22:19:18]

Done.

+  for (std::vector<std::string>::const_iterator it = columns.begin();
+       it != columns.end(); it++) {

[vandebo (ex-Chrome), 2013/03/29 21:35:07]

++it

[tommycli, 2013/04/01 22:19:18]

Done.

+    base::FilePath column_file_path = directory_path.Append(
+        table_prefix + *it + "." + kPmpExtension);
+
+    PmpColumnReader* column_reader = new PmpColumnReader();
+    column_readers.push_back(column_reader);
+
+    uint32 row_cnt;
+
+    if (!column_reader->InitFromFile(column_file_path, &row_cnt))
+      return false;
+
+    max_row_count = std::max(max_row_count, row_cnt);
+  }
+
+  // Actually succeeded. Set member data.

[vandebo (ex-Chrome), 2013/03/29 21:35:07]

Remove comment.

[tommycli, 2013/04/01 22:19:18]

Done.

+  column_readers_ = column_readers.Pass();
+  max_row_count_ = max_row_count;
+
+  return true;
+}
+
+uint32 PmpTableReader::RowCount() const {
+  return max_row_count_;
+}
+
+std::vector<const PmpColumnReader*> PmpTableReader::GetColumns() const {
+  std::vector<const PmpColumnReader*> readers;
+  std::copy(column_readers_.begin(), column_readers_.end(),
+            std::back_inserter(readers));
+  return readers;
+}
+
+}  // namespace fileapi