Apple-2-Tools/atrcopy
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Added transaction support to write & delete files.

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* if error occurs, disk image returned to state it was before the call
This commit is contained in:
Rob McMullen 2017-02-22 05:42:40 -08:00
parent ea92e91865
commit 7151739ad3
1 changed files with 45 additions and 23 deletions
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68
atrcopy/diskimages.py
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@ -377,6 +377,14 @@ class DiskImageBase(object):
# file writing methods # file writing methods
def begin_transaction(self):
state = self.bytes[:], self.style[:]
return state
def rollback_transaction(self, state):
self.bytes[:], self.style[:] = state
return
def write_file(self, filename, filetype, data): def write_file(self, filename, filetype, data):
"""Write data to a file on disk """Write data to a file on disk
@ -384,18 +392,25 @@ class DiskImageBase(object):
not enough space on disk or a free entry is not available in the not enough space on disk or a free entry is not available in the
catalog. catalog.
""" """
directory = self.directory_class(self.bytes_per_sector) state = self.begin_transaction()
self.get_directory(directory) try:
dirent = directory.add_dirent(filename, filetype) directory = self.directory_class(self.bytes_per_sector)
data = to_numpy(data) self.get_directory(directory)
sector_list = self.sector_list_class(self.bytes_per_sector, self.payload_bytes_per_sector, data, self.writeable_sector_class) dirent = directory.add_dirent(filename, filetype)
vtoc_segments = self.get_vtoc_segments() data = to_numpy(data)
vtoc = self.vtoc_class(self.bytes_per_sector, vtoc_segments) sector_list = self.sector_list_class(self.bytes_per_sector, self.payload_bytes_per_sector, data, self.writeable_sector_class)
directory.save_dirent(dirent, vtoc, sector_list) vtoc_segments = self.get_vtoc_segments()
self.write_sector_list(sector_list) vtoc = self.vtoc_class(self.bytes_per_sector, vtoc_segments)
self.write_sector_list(vtoc) directory.save_dirent(dirent, vtoc, sector_list)
self.write_sector_list(directory) self.write_sector_list(sector_list)
self.get_metadata() self.write_sector_list(vtoc)
self.write_sector_list(directory)
self.get_metadata()
except AtrError:
self.rollback_transaction(state)
raise
finally:
self.get_metadata()
def write_sector_list(self, sector_list): def write_sector_list(self, sector_list):
for sector in sector_list: for sector in sector_list:
@ -404,17 +419,24 @@ class DiskImageBase(object):
self.bytes[pos:pos + size] = sector.data self.bytes[pos:pos + size] = sector.data
def delete_file(self, filename): def delete_file(self, filename):
directory = self.directory_class(self.bytes_per_sector) state = self.begin_transaction()
self.get_directory(directory) try:
dirent = directory.find_dirent(filename) directory = self.directory_class(self.bytes_per_sector)
sector_list = dirent.get_sector_list(self) self.get_directory(directory)
vtoc_segments = self.get_vtoc_segments() dirent = directory.find_dirent(filename)
vtoc = self.vtoc_class(self.bytes_per_sector, vtoc_segments) sector_list = dirent.get_sector_list(self)
directory.remove_dirent(dirent, vtoc, sector_list) vtoc_segments = self.get_vtoc_segments()
self.write_sector_list(sector_list) vtoc = self.vtoc_class(self.bytes_per_sector, vtoc_segments)
self.write_sector_list(vtoc) directory.remove_dirent(dirent, vtoc, sector_list)
self.write_sector_list(directory) self.write_sector_list(sector_list)
self.get_metadata() self.write_sector_list(vtoc)
self.write_sector_list(directory)
self.get_metadata()
except AtrError:
self.rollback_transaction(state)
raise
finally:
self.get_metadata()
class WriteableSector(object): class WriteableSector(object):