Refactorise the policy_path_parser framework

chrome/browser/policy/policy_path_parser_linux.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 <pwd.h>
 #include <sys/types.h>
 #include <unistd.h>
 
 #include "chrome/browser/policy/policy_path_parser.h"
 
+#include "base/bind.h"
 #include "base/logging.h"
 
 namespace policy {
 
 namespace path_parser {
 
+namespace internal {
+
 const char* kMachineNamePolicyVarName = "${machine_name}";
 const char* kUserNamePolicyVarName = "${user_name}";
 
-// Replaces all variable occurrences in the policy string with the respective
-// system settings values.
-base::FilePath::StringType ExpandPathVariables(
-    const base::FilePath::StringType& untranslated_string) {
-  base::FilePath::StringType result(untranslated_string);
-  if (result.length() == 0)
-    return result;
-  // Sanitize quotes in case of any around the whole string.
-  if (result.length() > 1 &&
-      ((result[0] == '"' && result[result.length() - 1] == '"') ||
-      (result[0] == '\'' && result[result.length() - 1] == '\''))) {
-    // Strip first and last char which should be matching quotes now.
-    result = result.substr(1, result.length() - 2);
-  }
-  // Translate two special variables ${user_name} and ${machine_name}
-  size_t position = result.find(kUserNamePolicyVarName);
-  if (position != std::string::npos) {
-    struct passwd* user = getpwuid(geteuid());
-    if (user) {
-      result.replace(position, strlen(kUserNamePolicyVarName), user->pw_name);
-    } else {
-      LOG(ERROR) << "Username variable can not be resolved. ";
-    }
-  }
-  position = result.find(kMachineNamePolicyVarName);
-  if (position != std::string::npos) {
-    char machinename[255];
-    if (gethostname(machinename, 255) == 0) {
-      result.replace(position, strlen(kMachineNamePolicyVarName), machinename);
-    } else {
-      LOG(ERROR) << "Machine name variable can not be resolved.";
-    }
-  }
-  return result;
+bool GetUserName(base::FilePath::StringType* value) {
+  struct passwd* user = getpwuid(geteuid());
+  if (user)
+    *value = base::FilePath::StringType(user->pw_name);
+  else
+    LOG(ERROR) << "Username variable can not be resolved. ";
+  return (user != NULL);
 }
 
+bool GetMachineName(base::FilePath::StringType* value) {
+  char machinename[255];
+  int status;
+  if ((status = gethostname(machinename, 255)) == 0)
+    *value = base::FilePath::StringType(machinename);
+  else
+    LOG(ERROR) << "Machine name variable can not be resolved.";
+  return (status == 0);
+}
+
+// A table mapping variable name to their respective getvalue callbacks.
+const VariableNameAndValueCallback kVariableNameAndValueCallbacks[] = {
+    {kUserNamePolicyVarName, &GetUserName},
+    {kMachineNamePolicyVarName, &GetMachineName}};
+
+// Total number of entries in the mapping table.
+const int kNoOfVariables = arraysize(kVariableNameAndValueCallbacks);
+
+}  // namespace internal
+
 void CheckUserDataDirPolicy(base::FilePath* user_data_dir) {
   // This function is not implemented in Linux because we don't support the
   // policy on this platform.
   NOTREACHED();
 }
 
 }  // namespace path_parser
 
 }  // namespace policy