+static int
+get_system_compression_format(int extract_flags)
+{
+ if (extract_flags & WIMLIB_EXTRACT_FLAG_COMPACT_XPRESS4K)
+ return FILE_PROVIDER_COMPRESSION_FORMAT_XPRESS4K;
+
+ if (extract_flags & WIMLIB_EXTRACT_FLAG_COMPACT_XPRESS8K)
+ return FILE_PROVIDER_COMPRESSION_FORMAT_XPRESS8K;
+
+ if (extract_flags & WIMLIB_EXTRACT_FLAG_COMPACT_XPRESS16K)
+ return FILE_PROVIDER_COMPRESSION_FORMAT_XPRESS16K;
+
+ return FILE_PROVIDER_COMPRESSION_FORMAT_LZX;
+}
+
+static DWORD
+set_system_compression(HANDLE h, int format)
+{
+ DWORD bytes_returned;
+ DWORD err;
+ struct {
+ struct wof_external_info wof_info;
+ struct file_provider_external_info file_info;
+ } in = {
+ .wof_info = {
+ .version = WOF_CURRENT_VERSION,
+ .provider = WOF_PROVIDER_FILE,
+ },
+ .file_info = {
+ .version = FILE_PROVIDER_CURRENT_VERSION,
+ .compression_format = format,
+ },
+ };
+
+ if (DeviceIoControl(h, FSCTL_SET_EXTERNAL_BACKING, &in, sizeof(in),
+ NULL, 0, &bytes_returned, NULL))
+ return 0;
+
+ err = GetLastError();
+
+ if (err == 344) /* "Compressing this object would not save space." */
+ return 0;
+
+ return err;
+}
+
+/*
+ * This function is called when doing a "compact-mode" extraction and we just
+ * finished extracting a blob to one or more locations. For each location that
+ * was the unnamed data stream of a file, this function compresses the
+ * corresponding file using System Compression, if allowed.
+ *
+ * Note: we're doing the compression immediately after extracting the data
+ * rather than during a separate compression pass. This way should be faster
+ * since the operating system should still have the file's data cached.
+ *
+ * Note: we're having the operating system do the compression, which is not
+ * ideal because wimlib could create the compressed data faster and more
+ * efficiently (the compressed data format is identical to a WIM resource). But
+ * we seemingly don't have a choice because WOF prevents applications from
+ * creating its reparse points.
+ */
+static void
+handle_system_compression(struct blob_descriptor *blob, struct win32_apply_ctx *ctx)
+{
+ const struct blob_extraction_target *targets = blob_extraction_targets(blob);
+
+ const int format = get_system_compression_format(ctx->common.extract_flags);
+
+ for (u32 i = 0; i < blob->out_refcnt; i++) {
+ struct wim_inode *inode = targets[i].inode;
+ struct wim_inode_stream *strm = targets[i].stream;
+ HANDLE h;
+ NTSTATUS status;
+ DWORD err;
+
+ if (!stream_is_unnamed_data_stream(strm))
+ continue;
+
+ if (will_externally_back_inode(inode, ctx, NULL, false) != 0)
+ continue;
+
+ status = create_file(&h, GENERIC_READ | GENERIC_WRITE, NULL,
+ 0, FILE_OPEN, 0,
+ inode_first_extraction_dentry(inode), ctx);
+
+ if (NT_SUCCESS(status)) {
+ err = set_system_compression(h, format);
+ (*func_NtClose)(h);
+ } else {
+ err = (*func_RtlNtStatusToDosError)(status);
+ }
+
+ if (err == ERROR_INVALID_FUNCTION) {
+ WARNING(
+ "The request to compress the extracted files using System Compression\n"
+" will not be honored because the operating system or target volume\n"
+" does not support it. System Compression is only supported on\n"
+" Windows 10 and later, and only on NTFS volumes.");
+ ctx->common.extract_flags &= ~COMPACT_FLAGS;
+ return;
+ }
+
+ if (err) {
+ ctx->num_system_compression_failures++;
+ if (ctx->num_system_compression_failures < 10) {
+ win32_warning(err, L"\"%ls\": Failed to compress "
+ "extracted file using System Compression",
+ current_path(ctx));
+ } else if (ctx->num_system_compression_failures == 10) {
+ WARNING("Suppressing further warnings about "
+ "System Compression failures.");
+ }
+ }
+ }
+}
+
git://wimlib.net / wimlib / blobdiff