Merge pull request #114 from Changaco/various

libarchive/ffi.py

@@ -51,7 +51,9 @@
 )
 OPEN_CALLBACK = CFUNCTYPE(c_int, c_void_p, c_void_p)
 CLOSE_CALLBACK = CFUNCTYPE(c_int, c_void_p, c_void_p)
-VOID_CB = lambda *_: ARCHIVE_OK
+
+NO_OPEN_CB = ctypes.cast(None, OPEN_CALLBACK)
+NO_CLOSE_CB = ctypes.cast(None, CLOSE_CALLBACK)
 
 
 # Type aliases, for readability
@@ -79,7 +81,7 @@ def _error_string(archive_p):
 
 def archive_error(archive_p, retcode):
     msg = _error_string(archive_p)
-    raise ArchiveError(msg, errno(archive_p), retcode, archive_p)
+    return ArchiveError(msg, errno(archive_p), retcode, archive_p)
 
 
 def check_null(ret, func, args):
@@ -328,5 +330,5 @@ def get_write_filter_function(filter_name):
 except AttributeError:
     logger.info(
         f"the libarchive being used (version {version_number()}, "
-        f"path {ffi.libarchive_path}) doesn't support encryption"
+        f"path {libarchive_path}) doesn't support encryption"
     )

libarchive/read.py

@@ -5,7 +5,7 @@
 from . import ffi
 from .ffi import (
     ARCHIVE_EOF, OPEN_CALLBACK, READ_CALLBACK, CLOSE_CALLBACK, SEEK_CALLBACK,
-    VOID_CB, page_size,
+    NO_OPEN_CB, NO_CLOSE_CB, page_size,
 )
 from .entry import ArchiveEntry, new_archive_entry
 
@@ -57,15 +57,17 @@ def new_archive_read(format_name='all', filter_name='all', passphrase=None):
 @contextmanager
 def custom_reader(
     read_func, format_name='all', filter_name='all',
-    open_func=VOID_CB, close_func=VOID_CB, block_size=page_size,
-    archive_read_class=ArchiveRead, passphrase=None,
+    open_func=None, seek_func=None, close_func=None,
+    block_size=page_size, archive_read_class=ArchiveRead, passphrase=None,
 ):
     """Read an archive using a custom function.
     """
-    open_cb = OPEN_CALLBACK(open_func)
+    open_cb = OPEN_CALLBACK(open_func) if open_func else NO_OPEN_CB
     read_cb = READ_CALLBACK(read_func)
-    close_cb = CLOSE_CALLBACK(close_func)
+    close_cb = CLOSE_CALLBACK(close_func) if close_func else NO_CLOSE_CB
     with new_archive_read(format_name, filter_name, passphrase) as archive_p:
+        if seek_func:
+            ffi.read_set_seek_callback(archive_p, SEEK_CALLBACK(seek_func))
         ffi.read_open(archive_p, None, open_cb, read_cb, close_cb)
         yield archive_read_class(archive_p)
 
@@ -117,36 +119,9 @@ def stream_reader(
     """Read an archive from a stream.
 
     The `stream` object must support the standard `readinto` method.
-    """
-    buf = create_string_buffer(block_size)
-    buf_p = cast(buf, c_void_p)
 
-    def read_func(archive_p, context, ptrptr):
-        # readinto the buffer, returns number of bytes read
-        length = stream.readinto(buf)
-        # write the address of the buffer into the pointer
-        ptrptr = cast(ptrptr, POINTER(c_void_p))
-        ptrptr[0] = buf_p
-        # tell libarchive how much data was written into the buffer
-        return length
-
-    open_cb = OPEN_CALLBACK(VOID_CB)
-    read_cb = READ_CALLBACK(read_func)
-    close_cb = CLOSE_CALLBACK(VOID_CB)
-    with new_archive_read(format_name, filter_name, passphrase) as archive_p:
-        ffi.read_open(archive_p, None, open_cb, read_cb, close_cb)
-        yield ArchiveRead(archive_p)
-
-
-@contextmanager
-def seekable_stream_reader(
-    stream, format_name='all', filter_name='all', block_size=page_size,
-    passphrase=None,
-):
-    """Read an archive from a seekable stream.
-
-    The `stream` object must support the standard `readinto`, 'seek' and
-    'tell' methods.
+    If `stream.seekable()` returns `True`, then an appropriate seek callback is
+    passed to libarchive.
     """
     buf = create_string_buffer(block_size)
     buf_p = cast(buf, c_void_p)
@@ -165,11 +140,14 @@ def seek_func(archive_p, context, offset, whence):
         # tell libarchive the current position
         return stream.tell()
 
-    open_cb = OPEN_CALLBACK(VOID_CB)
+    open_cb = NO_OPEN_CB
     read_cb = READ_CALLBACK(read_func)
-    seek_cb = SEEK_CALLBACK(seek_func)
-    close_cb = CLOSE_CALLBACK(VOID_CB)
+    close_cb = NO_CLOSE_CB
     with new_archive_read(format_name, filter_name, passphrase) as archive_p:
-        ffi.read_set_seek_callback(archive_p, seek_cb)
+        if stream.seekable():
+            ffi.read_set_seek_callback(archive_p, SEEK_CALLBACK(seek_func))
         ffi.read_open(archive_p, None, open_cb, read_cb, close_cb)
         yield ArchiveRead(archive_p)
+
+
+seekable_stream_reader = stream_reader

libarchive/write.py

@@ -5,8 +5,8 @@
 from . import ffi
 from .entry import ArchiveEntry, new_archive_entry
 from .ffi import (
-    OPEN_CALLBACK, WRITE_CALLBACK, CLOSE_CALLBACK, VOID_CB, REGULAR_FILE,
-    DEFAULT_UNIX_PERMISSION, ARCHIVE_EOF,
+    OPEN_CALLBACK, WRITE_CALLBACK, CLOSE_CALLBACK, NO_OPEN_CB, NO_CLOSE_CB,
+    REGULAR_FILE, DEFAULT_UNIX_PERMISSION, ARCHIVE_EOF,
     page_size, entry_sourcepath, entry_clear, read_disk_new, read_disk_open_w,
     read_next_header2, read_disk_descend, read_free, write_header, write_data,
     write_finish_entry, entry_set_size, entry_set_filetype, entry_set_perm,
@@ -187,17 +187,17 @@ def new_archive_write(format_name, filter_name=None, options='', passphrase=None
 @contextmanager
 def custom_writer(
     write_func, format_name, filter_name=None,
-    open_func=VOID_CB, close_func=VOID_CB, block_size=page_size,
+    open_func=None, close_func=None, block_size=page_size,
     archive_write_class=ArchiveWrite, options='', passphrase=None,
 ):
 
     def write_cb_internal(archive_p, context, buffer_, length):
         data = cast(buffer_, POINTER(c_char * length))[0]
         return write_func(data)
 
-    open_cb = OPEN_CALLBACK(open_func)
+    open_cb = OPEN_CALLBACK(open_func) if open_func else NO_OPEN_CB
     write_cb = WRITE_CALLBACK(write_cb_internal)
-    close_cb = CLOSE_CALLBACK(close_func)
+    close_cb = CLOSE_CALLBACK(close_func) if close_func else NO_CLOSE_CB
 
     with new_archive_write(format_name, filter_name, options,
                            passphrase) as archive_p: