librsync actually blocks on output buffer size as well as input availability. So handle that

kittens/transfer/librsync.py

@@ -4,7 +4,7 @@
 
 import os
 import tempfile
-from typing import IO, TYPE_CHECKING, Iterator
+from typing import IO, TYPE_CHECKING, Iterator, Union
 
 from .rsync import (
     IO_BUFFER_SIZE, RsyncError, begin_create_delta, begin_create_signature,
@@ -22,34 +22,41 @@ class StreamingJob:
     def __init__(self, job: 'JobCapsule', output_buf_size: int = IO_BUFFER_SIZE):
         self.job = job
         self.finished = False
-        self.prev_unused_input = b''
         self.calls_with_no_data = 0
         self.output_buf = bytearray(output_buf_size)
+        self.uncomsumed_data = b''
 
-    def __call__(self, input_data: bytes = b'') -> memoryview:
+    def __call__(self, input_data: Union[memoryview, bytes] = b'') -> Iterator[memoryview]:
         if self.finished:
             if input_data:
                 raise RsyncError('There was too much input data')
             return memoryview(self.output_buf)[:0]
-        no_more_data = not input_data
+        if self.uncomsumed_data:
-        if self.prev_unused_input:
+            input_data = self.uncomsumed_data + bytes(input_data)
-            input_data = self.prev_unused_input + input_data
+            self.uncomsumed_data = b''
-            self.prev_unused_input = b''
+        while True:
             self.finished, sz_of_unused_input, output_size = iter_job(self.job, input_data, self.output_buf)
-        if sz_of_unused_input > 0 and not self.finished:
+            if output_size:
-            if no_more_data:
+                yield memoryview(self.output_buf)[:output_size]
-                raise RsyncError(f"{sz_of_unused_input} bytes of input data were not used")
-            self.prev_unused_input = bytes(input_data[-sz_of_unused_input:])
             if self.finished:
-            self.commit()
+                break
-        if no_more_data and not output_size:
+            if not sz_of_unused_input and len(input_data):
-            self.calls_with_no_data += 1
+                break
-        if self.calls_with_no_data > 3:  # prevent infinite loop
+            consumed_some_input = sz_of_unused_input < len(input_data)
-            raise RsyncError('There was not enough input data')
+            produced_some_output = output_size > 0
-        return memoryview(self.output_buf)[:output_size]
+            if not consumed_some_input and not produced_some_output:
+                break
+            input_data = memoryview(input_data)[-sz_of_unused_input:]
+        if sz_of_unused_input:
+            self.uncomsumed_data = bytes(input_data[-sz_of_unused_input:])
 
-    def commit(self) -> None:
+    def get_remaining_output(self) -> Iterator[memoryview]:
-        pass
+        if not self.finished:
+            yield from self()
+        if not self.finished:
+            raise RsyncError('Insufficient input data')
+        if self.uncomsumed_data:
+            raise RsyncError(f'{len(self.uncomsumed_data)} bytes if unconsumed input data')
 
 
 def drive_job_on_file(f: IO[bytes], job: 'JobCapsule', input_buf_size: int = IO_BUFFER_SIZE, output_buf_size: int = IO_BUFFER_SIZE) -> Iterator[memoryview]:
@@ -57,9 +64,11 @@ def drive_job_on_file(f: IO[bytes], job: 'JobCapsule', input_buf_size: int = IO_
     input_buf = bytearray(input_buf_size)
     while not sj.finished:
         sz = f.readinto(input_buf)  # type: ignore
-        result = sj(memoryview(input_buf)[:sz])
+        if not sz:
-        if len(result) > 0:
+            del input_buf
-            yield result
+            yield from sj.get_remaining_output()
+            break
+        yield from sj(memoryview(input_buf)[:sz])
 
 
 def signature_of_file(path: str) -> Iterator[memoryview]:
@@ -83,7 +92,13 @@ class LoadSignature(StreamingJob):
         job, self.signature = begin_load_signature()
         super().__init__(job, output_buf_size=0)
 
+    def add_chunk(self, chunk: bytes) -> None:
+        for ignored in self(chunk):
+            pass
+
     def commit(self) -> None:
+        for ignored in self.get_remaining_output():
+            pass
         build_hash_table(self.signature)
 
 
@@ -115,6 +130,7 @@ class PatchFile(StreamingJob):
 
     def close(self) -> None:
         if not self.src_file.closed:
+            self.get_remaining_output()
             self.src_file.close()
             count = 100
             while not self.finished:
@@ -127,8 +143,7 @@ class PatchFile(StreamingJob):
                 os.replace(self.dest_file.name, self.src_file.name)
 
     def write(self, data: bytes) -> None:
-        output = self(data)
+        for output in self(data):
-        if output:
             self.dest_file.write(output)
 
     def __enter__(self) -> 'PatchFile':
@@ -144,12 +159,10 @@ def develop() -> None:
     sig_loader = LoadSignature()
     with open(src + '.sig', 'wb') as f:
         for chunk in signature_of_file(src):
-            sig_loader(chunk)
+            sig_loader.add_chunk(chunk)
             f.write(chunk)
-    sig_loader()
+    sig_loader.commit()
     with open(src + '.delta', 'wb') as f, PatchFile(src, src + '.output') as patcher:
         for chunk in delta_for_file(src, sig_loader.signature):
             f.write(chunk)
             patcher.write(chunk)
-        if not patcher.finished:
-            patcher.write(b'')

kittens/transfer/rsync.c

@@ -89,27 +89,16 @@ iter_job(PyObject *self UNUSED, PyObject *args) {
         .avail_in=input_buf.len, .next_in=input_buf.buf, .eof_in=eof,
         .avail_out=output_buf.len, .next_out=output_buf.buf
     };
-    Py_ssize_t output_size = 0;
-    rs_result result = RS_DONE;
-    while (true) {
     size_t before = buffer.avail_out;
-        result = rs_job_iter(job, &buffer);
+    rs_result result = rs_job_iter(job, &buffer);
-        output_size += before - buffer.avail_out;
+    Py_ssize_t output_size = before - buffer.avail_out;
-        if (result == RS_DONE || result == RS_BLOCKED) break;
+    if (result == RS_DONE || result == RS_BLOCKED) {
-        if (buffer.avail_in) {
+        Py_ssize_t unused_input = buffer.avail_in;
-            PyBuffer_Release(&output_buf);
+        return Py_BuildValue("Onn", result == RS_DONE ? Py_True : Py_False, unused_input, output_size);
-            if (PyByteArray_Resize(output_array, MAX(IO_BUFFER_SIZE, (size_t)PyByteArray_GET_SIZE(output_array) * 2)) != 0) return NULL;
-            if (PyObject_GetBuffer(output_array, &output_buf, PyBUF_WRITE) != 0) return NULL;
-            buffer.avail_out = output_buf.len - output_size;
-            buffer.next_out = (char*)output_buf.buf + output_size;
-            continue;
     }
     PyErr_SetString(RsyncError, rs_strerror(result));
     return NULL;
 }
-    Py_ssize_t unused_input = buffer.avail_in;
-    return Py_BuildValue("Onn", result == RS_DONE ? Py_True : Py_False, unused_input, output_size);
-}
 
 static PyObject*
 begin_load_signature(PyObject *self UNUSED, PyObject *args UNUSED) {

kittens/transfer/send.py

@@ -392,8 +392,9 @@ class SendManager:
             return
         sl = file.signature_loader
         assert sl is not None
-        sl(ftc.data)
+        sl.add_chunk(ftc.data)
         if ftc.action is Action.end_data:
+            sl.commit()
             file.start_delta_calculation()
             self.update_collective_statuses()
 

kitty_tests/file_transmission.py

@@ -91,28 +91,38 @@ class TestFileTransmission(BaseTest):
         a_path = os.path.join(self.tdir, 'a')
         b_path = os.path.join(self.tdir, 'b')
         c_path = os.path.join(self.tdir, 'c')
+
+        def files_equal(a_path, c_path):
+            self.ae(os.path.getsize(a_path), os.path.getsize(b_path))
+            with open(b_path, 'rb') as b, open(c_path, 'rb') as c:
+                self.ae(b.read(), c.read())
+
+        def patch(old_path, new_path, output_path, max_delta_len=0):
+            sig_loader = LoadSignature()
+            for chunk in signature_of_file(old_path):
+                sig_loader.add_chunk(chunk)
+            sig_loader.commit()
+            self.assertTrue(sig_loader.finished)
+            delta_len = 0
+            with PatchFile(old_path, output_path) as patcher:
+                for chunk in delta_for_file(new_path, sig_loader.signature):
+                    self.assertFalse(patcher.finished)
+                    patcher.write(chunk)
+                    delta_len += len(chunk)
+            self.assertTrue(patcher.finished)
+            if max_delta_len:
+                self.assertLessEqual(delta_len, max_delta_len)
+            files_equal(output_path, new_path)
+
         sz = 1024 * 1024 + 37
         with open(a_path, 'wb') as f:
             f.write(os.urandom(sz))
         with open(b_path, 'wb') as f:
             f.write(os.urandom(sz))
-        sig_loader = LoadSignature()
+
-        for chunk in signature_of_file(a_path):
+        patch(a_path, b_path, c_path)
-            sig_loader(chunk)
+        # test size of delta
-        sig_loader()
+        patch(a_path, a_path, c_path, max_delta_len=256)
-        self.assertTrue(sig_loader.finished)
-        with PatchFile(a_path, c_path) as patcher:
-            for chunk in delta_for_file(b_path, sig_loader.signature):
-                self.assertFalse(patcher.finished)
-                patcher.write(chunk)
-        self.assertTrue(patcher.finished)
-        with open(b_path, 'rb') as b, open(c_path, 'rb') as c:
-            while True:
-                bc = b.read(4096)
-                cc = c.read(4096)
-                self.ae(bc, cc)
-                if not bc and not cc:
-                    break
 
     def test_file_put(self):
         # send refusal