/**
* Searches the directory for a data page with enough free space to store a record of the given
* size. If no suitable page is found, this creates a new data page.
*/
protected PageId getAvailPage(int reclen) {
for (int i = 0; i < pages.size(); i++) {
PageId pid = pages.get(i);
Page page = new Page();
global.Minibase.BufferManager.pinPage(pid, page, false);
HFPage hfpage = new HFPage();
hfpage.copyPage(page);
if (hfpage.getFreeSpace() >= reclen) {
global.Minibase.BufferManager.unpinPage(pid, true);
return pid;
}
global.Minibase.BufferManager.unpinPage(pid, false);
}
Page page = new Page();
PageId pid = global.Minibase.BufferManager.newPage(page, 1);
HFPage hfpage = new HFPage(page);
// initialize HFPage
hfpage.setCurPage(pid);
pages.add(pid);
pids.add(pid.pid);
current.setNextPage(pid);
hfpage.setPrevPage(current.getCurPage());
current = hfpage;
global.Minibase.BufferManager.unpinPage(pid, true);
return pid;
}
/**
* Deletes the specified record from the heap file.
*
* @throws IllegalArgumentException if the rid is invalid
*/
public boolean deleteRecord(RID rid) {
PageId pid = rid.pageno;
if (!pids.contains(pid.pid)) throw new IllegalArgumentException("the rid is invalid");
try {
Page page = new Page();
global.Minibase.BufferManager.pinPage(pid, page, false);
HFPage hfpage = new HFPage();
hfpage.copyPage(page);
hfpage.deleteRecord(rid);
global.Minibase.BufferManager.unpinPage(pid, true);
recordNumber--;
return true;
} catch (Exception e) {
System.err.print("fail to delete record");
return false;
}
}
