def write(self, path, data, offset, fh):
# print "Writing", data, path, offset, fh
meta = getmetadata(path)
dblocks = meta['blocks']
whichblock = offset / BLOCKSIZE
whereinblock = offset % BLOCKSIZE
if whichblock >= len(dblocks):
curblock = ""
else:
curblock = getblock(dblocks[whichblock])
datalen = min(len(data), BLOCKSIZE) #only write one block at a time
data = data[:datalen] #truncate data that can't be written
curblock = curblock[:offset] + data + curblock[offset + datalen:]
blockname = nameblock(curblock)
putblock(blockname, curblock) #store the new block
#now update the metadata
if whichblock < len(dblocks):
dblocks[whichblock] = blockname
else:
#new block, need to update the size
sze = BLOCKSIZE * len(dblocks) #how many full blocks do we have?
sze += len(curblock) #add in the length of the current block
#New block, update size
dblocks += [blockname]
meta['st_size'] = sze
meta['blocks'] = dblocks
setmetadata(path, meta)
return min(len(data), BLOCKSIZE)
def truncate(self, path, length, fh=None):
#truncate path to length bytes
meta = getmetadata(path)
dblocks = meta['blocks']
numblocks = length / BLOCKSIZE
lastblocklen = length % BLOCKSIZE
dblocks = dblocks[:numblocks]
if len(dblocks) == 0:
meta['blocks'] = dblocks
setmetadata(path, meta)
return
lastblock = getblock(dblocks[-1])
lastblock = lastblock[:lastblocklen]
blockname = nameblock[block]
putblock(blockname, lastblock)
dblocks[-1] = blockname
meta['blocks'] = dblocks
setmetadata(path, meta)
def setmetadata(path, meta):
# print "Setting", path, "metadata to", meta
putblock('METADATA=' + path, simplejson.dumps(meta))
