bitbake: bitbake: Add piping compression library

Adds a library that implements file-like objects (similar to
gzip.GzipFile) that can stream to arbitrary compression programs. This
is utilized to implement a LZ4 and zstd compression API.

(Bitbake rev: 61c3acd058ea018696bd284b3922d0b458838d05)

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/compress/zstd.py

@@ -0,0 +1,28 @@
+#
+# SPDX-License-Identifier: GPL-2.0-only
+#
+
+import bb.compress._pipecompress
+import shutil
+
+
+def open(*args, **kwargs):
+    return bb.compress._pipecompress.open_wrap(ZstdFile, *args, **kwargs)
+
+
+class ZstdFile(bb.compress._pipecompress.PipeFile):
+    def __init__(self, *args, num_threads=1, compresslevel=3, **kwargs):
+        self.num_threads = num_threads
+        self.compresslevel = compresslevel
+        super().__init__(*args, **kwargs)
+
+    def _get_zstd(self):
+        if self.num_threads == 1 or not shutil.which("pzstd"):
+            return ["zstd"]
+        return ["pzstd", "-p", "%d" % self.num_threads]
+
+    def get_compress(self):
+        return self._get_zstd() + ["-c", "-%d" % self.compresslevel]
+
+    def get_decompress(self):
+        return self._get_zstd() + ["-d", "-c"]