1 files changed, 170 insertions, 0 deletions
diff --git a/gamechestcli/remove.py b/gamechestcli/remove.py
new file mode 100644
index 0000000..00247f7
--- /dev/null
+++ b/gamechestcli/remove.py
@@ -0,0 +1,170 @@
+#!/usr/bin/python3
+
+import io
+import os
+import re
+import subprocess
+import threading
+
+import humanfriendly
+
+from structures import Progress
+
+
+class Remove:
+
+    _progress_re = re.compile(r'^\s*(\S+)\s+\[([^]]+)/s\]\s+ETA\s+(\S+)\s*$')
+
+    def __init__(self, path):
+        self.last_progress = Progress()
+        self.path = path
+        self.rm_proc = None
+        self.pv_proc = None
+        self.pipe = os.pipe()
+        self.read_fd = io.open(self.pipe[0], 'r', encoding='utf8')
+        self._proc_started = False
+        self._filescount = 0
+        self._counting_quit_event = threading.Event()
+        self._counting_thread = threading.Thread(
+            target=self._counting_worker,
+            args=(self._counting_quit_event, path),
+        )
+        self._counting_thread.start()
+
+    def _start_proc(self):
+        common_parameters = dict(
+            encoding='utf8',
+            env={**os.environ,
+                 **{'LC_ALL':'C.UTF-8',
+                    'LANG':'C.UTF-8',
+                    'LANGUAGE':'C.UTF-8',
+                    }},
+        )
+        self.rm_proc = subprocess.Popen(
+            [
+                'rm',
+                '--verbose',
+                '--recursive',
+                '--one-file-system',
+                '--preserve-root=all',
+                '--interactive=never',
+                '--',
+                self.path,
+            ],
+            stdout=subprocess.PIPE,
+            **common_parameters,
+        )
+        #self.rm_proc = subprocess.Popen(  # only for testing purposes
+        #    [
+        #        'testtools/fake-rm',
+        #        self.path,
+        #    ],
+        #    stdout=subprocess.PIPE,
+        #    **common_parameters,
+        #)
+        self.pv_proc = subprocess.Popen(
+            [
+                'pv',
+                '--force',
+                '--size', str(self._filescount),
+                '--format', '%b %a %e',
+                '--line-mode',
+            ],
+            stdin=self.rm_proc.stdout,
+            stdout=subprocess.DEVNULL,
+            stderr=self.pipe[1],
+            **common_parameters,
+        )
+        # close child's pipe fd on parent's side or selectors will hang if
+        # process closes.
+        os.close(self.pipe[1])
+        self._proc_started = True
+
+    def _counting_worker(self, event, path):
+        # as counting files for a deep directory can take some time, make it
+        # interruptible with a thread and event for cancelling.
+        # using functools.reduce(x+1+len(y[2]), os.walk) would have been much
+        # cleaner, but the code gets harder to read with the addition of the
+        # event checking. Fallback to accumalator and iterations.
+        total = 0
+        for _, _, files in os.walk(path):
+            total += 1 + len(files)
+            if event.is_set():
+                break
+        # set filescount with calculated total (even then interrupted, as it
+        # would be a better estimation than nothing).
+        self._filescount = total
+        # start next processes (if event was not set)
+        if not event.is_set():
+            self._start_proc()
+
+    def select_fd(self):
+        'useful to use selectors with the process most meaningful fd'
+        return self.read_fd
+
+    def progress_read(self):
+        if not self._proc_started:
+            return self.last_progress
+        line = self.read_fd.readline()
+        if match := self._progress_re.search(line):
+            written_bytes = humanfriendly.parse_size(match.group(1))
+            self.last_progress = Progress(
+                written_bytes,
+                int(100 * written_bytes / self._filescount),
+                humanfriendly.parse_size(match.group(2)),
+                match.group(3),
+            )
+        return self.last_progress
+
+    def terminate(self):
+        if self._proc_started:
+            for proc in (self.rm_proc, self.pv_proc):
+                proc.terminate()
+        else:
+            self._counting_quit_event.set()
+
+    def poll(self):
+        'returns None if not terminated, otherwise return returncode'
+        if not self._proc_started:
+            return None
+        return self.pv_proc.poll()
+
+    def wait(self, timeout=None):
+        if self._proc_started:
+            self.rm_proc.wait(timeout)
+            return self.pv_proc.wait(timeout)
+        else:
+            self._counting_thread.join(timeout)
+            return -1
+
+    def close(self):
+        self.read_fd.close()
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, value, traceback):
+        self.terminate()
+        self.wait()
+        self.close()
+
+
+if __name__ == '__main__':
+    import sys
+    import contextlib
+    import time
+    import selectors
+
+    with contextlib.ExitStack() as stack:
+        stack.enter_context(contextlib.suppress(KeyboardInterrupt))
+        remove = stack.enter_context(Remove(sys.argv[1]))
+        selector = stack.enter_context(selectors.DefaultSelector())
+        selector.register(remove.select_fd(), selectors.EVENT_READ)
+        while remove.poll() is None:
+            selector.select()
+            progress = remove.progress_read()
+            print(f'{progress.bytes}b {progress.percent}% '
+                f'{progress.speed}b/s {progress.eta}')
+        rc = remove.poll()
+        print(f'ended with code: {rc}')
+    print('test main ended')