Implement CSVReader and CSVWriter to be used for password import and export.

components/password_manager/core/browser/export/csv_writer.cc

Index: components/password_manager/core/browser/export/csv_writer.cc
diff --git a/components/password_manager/core/browser/export/csv_writer.cc b/components/password_manager/core/browser/export/csv_writer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..eef3c39cdfd33eb6fafb58ab0c8022522a025109
--- /dev/null
+++ b/components/password_manager/core/browser/export/csv_writer.cc
@@ -0,0 +1,92 @@
+// Copyright 2014 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 "components/password_manager/core/browser/export/csv_writer.h"
+
+#include "base/logging.h"
+#include "base/strings/string_util.h"
+#include "build/build_config.h"
+
+namespace {
+
+// Encapsulates formatting and outputting values to a CSV file row by row. Takes
+// care of escaping and adding the appropriate separators.
+class CSVFormatter {
+ public:
+  explicit CSVFormatter(std::string* output)
+      : output_(output), at_beginning_of_line_(true) {}
+
+  // Escapes the |raw_value| if needed, adds a field separator unless we are at
+  // the beginning of a line, and appends the escaped value to |output_|.
+  void AppendValue(const std::string& raw_value);
+
+  // Appends the platform-specific EOL terminator to |output_|.
+  void EndLine();
+
+ private:
+  std::string* output_;
+  bool at_beginning_of_line_;
+};
+
+void CSVFormatter::AppendValue(const std::string& raw_value) {
+  // Append the field separator unless this is the first field on the line.
+  if (!at_beginning_of_line_)
+    output_->push_back(',');
+  at_beginning_of_line_ = false;
+
+  // Fields containing line breaks (CRLF), double quotes, and commas should be
+  // enclosed in double-quotes. If double-quotes are used to enclose fields,
+  // then double-quotes appearing inside a field must be escaped by preceding
+  // them with another double quote.
+  if (raw_value.find_first_of("\r\n\",") != std::string::npos) {
+    output_->push_back('\"');
+    output_->append(raw_value);
+    ReplaceSubstringsAfterOffset(
+        output_, output_->size() - raw_value.size(), "\"", "\"\"");
+    output_->push_back('\"');
+  } else {
+    output_->append(raw_value);
+  }
+}
+
+void CSVFormatter::EndLine() {
+#if defined(OS_WIN)
+  const char kLineEnding[] = "\r\n";
+#else
+  const char kLineEnding[] = "\n";
+#endif
+  output_->append(kLineEnding);
+  at_beginning_of_line_ = true;
+}
+
+}  // namespace
+
+namespace password_manager {
+
+void WriteCSV(
+    const std::vector<std::string>& column_names,
+    const std::vector<std::map<std::string, std::string>>& records,
+    std::string* csv) {
+  DCHECK(csv);
+  csv->clear();
+
+  // Append header row.
+  CSVFormatter formatter(csv);
+  for (const auto& column_name : column_names) {
+    formatter.AppendValue(column_name);
+  }
+  formatter.EndLine();
+
+  // Append every other data record row.
+  for (const auto& row : records) {
+    for (const auto& column_name : column_names) {
+      auto it_field = row.find(column_name);
+      formatter.AppendValue(it_field != row.end() ?
+          it_field->second : std::string());
+    }
+    formatter.EndLine();
+  }
+}
+
+}  // namespace password_manager