define(function() {
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//we don't use dojo's declare to define class
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//because this function will be used in node.js
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function BaseVersionManager(){
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/******************************************************
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element signature:
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{
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//the version you want to upgrade to. version format: 1.0.0
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version: '',
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//the version discription
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description: '',
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//the upgrade logic to upgrade from the latest old verion to this version
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//the first upgrader will upgrade unknow version to the first version
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upgrader: function(oldConfig){
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//your logic here
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return newConfig;
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}
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}
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******************************************************/
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this.versions = [];
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this.upgrade = function(config, _oldVersion, _newVersion){
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//the config is the old version
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//method should return new upgraded config
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var oldVersionIndex = this.getVersionIndex(_oldVersion);
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var newVersionIndex = this.getVersionIndex(_newVersion);
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if(oldVersionIndex > newVersionIndex){
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throw Error('New version should higher than old version.');
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}
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var newConfig = config, i;
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for(i = oldVersionIndex + 1; i <= newVersionIndex; i++){
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if(!this.versions[i].upgrader){
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//if no upgrader, we consider the version is compatible
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continue;
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}
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newConfig = this.versions[i].upgrader(newConfig);
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}
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return newConfig;
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};
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this.getVersionIndex = function(_version){
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var version = this.fixVersion(_version);
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var versionIndex, i;
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for(i = 0; i < this.versions.length; i++){
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if(this.versions[i].version === version){
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versionIndex = i;
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}
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}
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//if there is no version, we assume it's very old and will upgrade from the first version
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if(version === null){
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versionIndex = -1;
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}
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if(versionIndex === undefined){
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//for unknown version, we assume it's the latest version but it's not in versions array.
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versionIndex = this.versions.length - 1;
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}
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return versionIndex;
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};
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this.fixVersion = function(version){
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if(!version){
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return null;
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}
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return version;
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//TODO
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};
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}
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return BaseVersionManager;
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});
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