Refactoring the master_preferences functions....

chrome/installer/util/master_preferences.h

Index: chrome/installer/util/master_preferences.h
===================================================================
--- chrome/installer/util/master_preferences.h	(revision 64604)
+++ chrome/installer/util/master_preferences.h	(working copy)
@@ -12,8 +12,8 @@
 #include <vector>
 
 #include "base/command_line.h"
+#include "base/scoped_ptr.h"
 #include "googleurl/src/gurl.h"
-#include "chrome/installer/util/master_preferences_constants.h"
 
 class DictionaryValue;
 class FilePath;
@@ -24,30 +24,6 @@
 // values in the user profile at first run.
 const char kDefaultMasterPrefs[] = "master_preferences";
 
-// Parse command line and read master preferences, if present, to get
-// distribution related install options. Merge them if any command line
-// options present (command line value takes precedence).
-DictionaryValue* GetInstallPreferences(const CommandLine& cmd_line);
-
-// Gets the value of given boolean preference |name| from |prefs| dictionary
-// which is assumed to contain a dictionary named "distribution". Returns
-// true if the value is read successfully, otherwise false.
-bool GetDistroBooleanPreference(const DictionaryValue* prefs,
-                                const std::string& name,
-                                bool* value);
-
-// This function gets value of a string preference from master
-// preferences. Returns true if the value is read successfully, otherwise false.
-bool GetDistroStringPreference(const DictionaryValue* prefs,
-                               const std::string& name,
-                               std::string* value);
-
-// This function gets value of an integer preference from master
-// preferences. Returns true if the value is read successfully, otherwise false.
-bool GetDistroIntegerPreference(const DictionaryValue* prefs,
-                                const std::string& name,
-                                int* value);
-
 // The master preferences is a JSON file with the same entries as the
 // 'Default\Preferences' file. This function parses the distribution
 // section of the preferences file.
@@ -93,69 +69,95 @@
 // installation properties. This entry will be ignored at other times.
 // This function parses the 'distribution' entry and returns a combination
 // of MasterPrefResult.
-DictionaryValue* ParseDistributionPreferences(
-    const FilePath& master_prefs_path);
+class MasterPreferences {
+ public:
+  // Parses the command line and optionally reads the master preferences file
+  // to get distribution related install options (if the "installerdata" switch
+  // is present in the command line.
+  // The options from the preference file and command line are merged, with the
+  // ones from the command line taking precedence in case of a conflict.
+  explicit MasterPreferences(const CommandLine& cmd_line);
 
-// As part of the master preferences an optional section indicates the tabs
-// to open during first run. An example is the following:
-//
-//  {
-//    "first_run_tabs": [
-//       "http://google.com/f1",
-//       "https://google.com/f2"
-//    ]
-//  }
-//
-// Note that the entries are usually urls but they don't have to.
-//
-// This function retuns the list as a vector of GURLs.  If the master
-// preferences file does not contain such list the vector is empty.
-std::vector<GURL> GetFirstRunTabs(const DictionaryValue* prefs);
+  // Parses a specific preferences file and does not merge any command line
+  // switches with the distribution dictionary.
+  explicit MasterPreferences(const FilePath& prefs_path);
 
-// Sets the value of given boolean preference |name| in "distribution"
-// dictionary inside |prefs| dictionary.
-bool SetDistroBooleanPreference(DictionaryValue* prefs,
-                                const std::string& name,
-                                bool value);
+  ~MasterPreferences();
 
-// The master preferences can also contain a regular extensions
-// preference block. If so, the extensions referenced there will be
-// installed during the first run experience.
-// An extension can go in the master prefs needs just the basic
-// elements such as:
-//   1- An extension entry under settings, assigned by the gallery
-//   2- The "location" : 1 entry
-//   3- A minimal "manifest" block with key, name, permissions, update url
-//      and version. The version needs to be lower than the version of
-//      the extension that is hosted in the gallery.
-//   4- The "path" entry with the version as last component
-//   5- The "state" : 1 entry
-//
-// The following is an example of a master pref file that installs
-// Google XYZ:
-//
-//  {
-//     "extensions": {
-//        "settings": {
-//           "ppflmjolhbonpkbkooiamcnenbmbjcbb": {
-//              "location": 1,
-//              "manifest": {
-//                 "key": "MIGfMA0GCSqGSIb3DQEBAQUAA4<rest of key ommited>",
-//                 "name": "Google XYZ (Installing...)",
-//                 "permissions": [ "tabs", "http://xyz.google.com/" ],
-//                 "update_url": "http://fixme.com/fixme/fixme/crx",
-//                 "version": "0.0"
-//              },
-//              "path": "ppflmjolhbonpkbkooiamcnenbmbjcbb\\0.0",
-//              "state": 1
-//           }
-//        }
-//     }
-//  }
-//
-bool HasExtensionsBlock(const DictionaryValue* prefs,
-                        DictionaryValue** extensions);
+  // Each of the Get methods below returns true if the named value was found in
+  // the distribution dictionary and its value assigned to the 'value'
+  // parameter.  If the value wasn't found, the return value is false.
+  bool GetBool(const std::string& name, bool* value) const;
+  bool GetInt(const std::string& name, int* value) const;
+  bool GetString(const std::string& name, std::string* value) const;
 
+  // As part of the master preferences an optional section indicates the tabs
+  // to open during first run. An example is the following:
+  //
+  //  {
+  //    "first_run_tabs": [
+  //       "http://google.com/f1",
+  //       "https://google.com/f2"
+  //    ]
+  //  }
+  //
+  // Note that the entries are usually urls but they don't have to be.
+  //
+  // This function returns the list as a vector of GURLs.  If the master
+  // preferences file does not contain such a list the vector is empty.
+  std::vector<GURL> GetFirstRunTabs() const;
+
+  // The master preferences can also contain a regular extensions
+  // preference block. If so, the extensions referenced there will be
+  // installed during the first run experience.
+  // An extension can go in the master prefs needs just the basic
+  // elements such as:
+  //   1- An extension entry under settings, assigned by the gallery
+  //   2- The "location" : 1 entry
+  //   3- A minimal "manifest" block with key, name, permissions, update url
+  //      and version. The version needs to be lower than the version of
+  //      the extension that is hosted in the gallery.
+  //   4- The "path" entry with the version as last component
+  //   5- The "state" : 1 entry
+  //
+  // The following is an example of a master pref file that installs
+  // Google XYZ:
+  //
+  //  {
+  //     "extensions": {
+  //        "settings": {
+  //           "ppflmjolhbonpkbkooiamcnenbmbjcbb": {
+  //              "location": 1,
+  //              "manifest": {
+  //                 "key": "MIGfMA0GCSqGSIb3DQEBAQUAA4<rest of key ommited>",
+  //                 "name": "Google XYZ (Installing...)",
+  //                 "permissions": [ "tabs", "http://xyz.google.com/" ],
+  //                 "update_url": "http://fixme.com/fixme/fixme/crx",
+  //                 "version": "0.0"
+  //              },
+  //              "path": "ppflmjolhbonpkbkooiamcnenbmbjcbb\\0.0",
+  //              "state": 1
+  //           }
+  //        }
+  //     }
+  //  }
+  //
+  bool GetExtensionsBlock(DictionaryValue** extensions) const;
+
+  // Returns true iff the master preferences were successfully read from a file.
+  bool read_from_file() const {
+    return preferences_read_from_file_;
+  }
+
+ protected:
+  scoped_ptr<DictionaryValue> master_dictionary_;
+  DictionaryValue* distribution_;
+  bool preferences_read_from_file_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(MasterPreferences);
+};
+
 }  // namespace installer_util
 
 #endif  // CHROME_INSTALLER_UTIL_MASTER_PREFERENCES_H_