Refactoring the SysInfoProvider.

chrome/browser/chromeos/syslogs/lsbrelease_fetcher.cc

+// Copyright (c) 2012 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 "chrome/browser/chromeos/syslogs/lsbrelease_fetcher.h"
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/file_path.h"
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "base/string_util.h"
+
+
+namespace chromeos {
+
+// TODO(tudalex): Replace this code with a more simpler code based on a string
+// tokenizer
+
+// The following code is copied form SysLogsProvider
+const char kMultilineQuote[] = "\"\"\"";
+const char kNewLineChars[] = "\r\n";
+const char kInvalidLogEntry[] = "<invalid characters in log entry>";
+const char kEmptyLogEntry[] = "<no value>";
+
+// Reads a key from the input string erasing the read values + delimiters read
+// from the initial string
+std::string ReadKey(std::string* data) {
+  size_t equal_sign = data->find("=");
+  if (equal_sign == std::string::npos)
+    return std::string("");
+  std::string key = data->substr(0, equal_sign);
+  data->erase(0, equal_sign);
+  if (data->size() > 0) {
+    // erase the equal to sign also
+    data->erase(0,1);
+    return key;
+  }
+  return std::string();
+}
+
+// Reads a value from the input string; erasing the read values from
+// the initial string; detects if the value is multiline and reads
+// accordingly
+std::string ReadValue(std::string* data) {
+  // Trim the leading spaces and tabs. In order to use a multi-line
+  // value, you have to place the multi-line quote on the same line as
+  // the equal sign.
+  //
+  // Why not use TrimWhitespace? Consider the following input:
+  //
+  // KEY1=
+  // KEY2=VALUE
+  //
+  // If we use TrimWhitespace, we will incorrectly trim the new line
+  // and assume that KEY1's value is "KEY2=VALUE" rather than empty.
+  TrimString(*data, " \t", data);
+
+  // If multiline value
+  if (StartsWithASCII(*data, std::string(kMultilineQuote), false)) {
+    data->erase(0, strlen(kMultilineQuote));
+    size_t next_multi = data->find(kMultilineQuote);
+    if (next_multi == std::string::npos) {
+      // Error condition, clear data to stop further processing
+      data->erase();
+      return std::string();
+    }
+    std::string value = data->substr(0, next_multi);
+    data->erase(0, next_multi + 3);
+    return value;
+  } else { // single line value
+    size_t endl_pos = data->find_first_of(kNewLineChars);
+    // if we don't find a new line, we just return the rest of the data
+    std::string value = data->substr(0, endl_pos);
+    data->erase(0, endl_pos);
+    return value;
+  }
+}
+
+void LSBReleaseFetcher::Fetch(SysLogsFetcherCallback request) {
+  SysLogsResponse* response = new SysLogsResponse;
+  FilePath lsb_release_file("/etc/lsb-release");
+  std::string data;
+  bool read_success = file_util::ReadFileToString(lsb_release_file,
+                                                      &data);
+  // if we were using an internal temp file, the user does not need the
+  // logs to stay past the ReadFile call - delete the file
+  if (!read_success)
+  {
+    LOG(ERROR)<<"Can't access /etc/lsb-release file.";
+    request.Run(response);
+    return;
+  }
+  while (data.length() > 0) {
+    std::string key = ReadKey(&data);
+    TrimWhitespaceASCII(key, TRIM_ALL, &key);
+    if (!key.empty()) {
+      std::string value = ReadValue(&data);
+      if (IsStringUTF8(value)) {
+        TrimWhitespaceASCII(value, TRIM_ALL, &value);
+        if (value.empty())
+          (*response)[key] = kEmptyLogEntry;
+        else
+          (*response)[key] = value;
+      } else {
+        LOG(WARNING) << "Invalid characters in system log entry: " << key;
+        (*response)[key] = kInvalidLogEntry;
+      }
+    } else {
+      // no more keys, we're done
+      break;
+    }
+  }
+  request.Run(response);
+}
+
+}  // namespace chromeos