/**
* Constructor.
*
* Created the master file which stores all the meta data about various distributed file systems.
*/
DistributedFileSystemManager :: DistributedFileSystemManager(const string root_path) {
this->root_path = root_path;
// Create meta data file.
const string path = root_path + "/" + METADATA_FILE;
FileManager fileManager;
if (!fileManager.findIfExists(path) && !fileManager.createFile (path, "")) {
cout << "Failed to create DFS manager metadata file." << endl;
exit(1);
}
}
void init() {
FileManager* fm = new FileManager();
BufPageManager* bpm = new BufPageManager(fm);
fm->createFile("testfile.txt"); //新建文件
int fileID;
fm->openFile("testfile.txt", fileID); //打开文件，fileID是返回的文件id
int index;
BufType b = bpm->allocPage(fileID, 0, index, true);
b[0] = 256;
b[1] = 100;
b[2] = 0;
b[3] = 0;
for (int i = 0; i < b[1]; i++) {
b[i+4] = 0;
}
bpm->markDirty(index);
fm->writePage(fileID, 0, b, 0);
bpm->close();
}
int main() {
FileManager* fm = new FileManager();
BufPageManager* bpm = new BufPageManager(fm);
fm->createFile("testfile.txt"); //新建文件
int fileID;
fm->openFile("testfile.txt", fileID); //打开文件，fileID是返回的文件id
for (int pageID = 0; pageID < 1000; ++ pageID) {
int index;
//为pageID获取一个缓存页
BufType b = bpm->allocPage(fileID, pageID, index, false);
b[0] = pageID; //对缓存页进行写操作
bpm->markDirty(index); //标记脏页
}
for (int pageID = 0; pageID < 1000; ++ pageID) {
int index;
//为pageID获取一个缓存页
BufType b = bpm->getPage(fileID, pageID, index);
cout << b[0] << endl; //读取缓存页中第一个整数
bpm->access(index); //标记访问
}
return 0;
}