同步客户绑定与登录恢复优化

scripts/runtime_state.py

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+"""Local configuration snapshots and bounded, process-safe updates."""
+import copy
+import errno
+import json
+import os
+import tempfile
+import time
+from contextlib import contextmanager
+
+
+class ConfigSnapshot(dict):
+    def __init__(self, values):
+        super().__init__(values)
+        self.original = copy.deepcopy(values)
+
+
+@contextmanager
+def file_lock(path, timeout=45):
+    # An OS lock is released even if the owning process crashes. Do not delete
+    # the lock file: replacing its inode would break coordination on POSIX.
+    with open(path, "a+b") as handle:
+        handle.seek(0, os.SEEK_END)
+        if handle.tell() == 0:
+            handle.write(b"\0")
+            handle.flush()
+        deadline = time.monotonic() + timeout
+        while True:
+            try:
+                if os.name == "nt":
+                    import msvcrt
+                    handle.seek(0)
+                    msvcrt.locking(handle.fileno(), msvcrt.LK_NBLCK, 1)
+                else:
+                    import fcntl
+                    fcntl.flock(handle.fileno(), fcntl.LOCK_EX | fcntl.LOCK_NB)
+                break
+            except OSError as exc:
+                if exc.errno not in (errno.EACCES, errno.EAGAIN, errno.EDEADLK):
+                    raise
+                if time.monotonic() >= deadline:
+                    raise TimeoutError("等待本机登录/配置锁超过 %s 秒" % timeout)
+                time.sleep(0.05)
+        try:
+            yield
+        finally:
+            if os.name == "nt":
+                handle.seek(0)
+                msvcrt.locking(handle.fileno(), msvcrt.LK_UNLCK, 1)
+            else:
+                fcntl.flock(handle.fileno(), fcntl.LOCK_UN)
+
+
+def read_config(path):
+    with open(path, "r", encoding="utf-8-sig") as handle:
+        return ConfigSnapshot(json.load(handle))
+
+
+def update_config(path, values, ignored=(), initialize=False):
+    """Merge only changed fields into the latest file, then atomically replace it."""
+    original = getattr(values, "original", {})
+    changes = {key: value for key, value in values.items()
+               if key not in ignored and (key not in original or value != original[key])}
+    removed = {key for key in original if key not in values and key not in ignored}
+    with file_lock(path + ".lock"):
+        try:
+            latest = read_config(path)
+            if initialize:
+                return latest
+        except FileNotFoundError:
+            latest = {}
+        if not changes and not removed and os.path.exists(path):
+            return ConfigSnapshot(latest)
+        latest.update(changes)
+        for key in removed:
+            latest.pop(key, None)
+        fd, temporary = tempfile.mkstemp(prefix="config.json.", suffix=".tmp", dir=os.path.dirname(path))
+        try:
+            with os.fdopen(fd, "w", encoding="utf-8") as handle:
+                json.dump(latest, handle, ensure_ascii=False, indent=2)
+                handle.flush()
+                os.fsync(handle.fileno())
+            os.replace(temporary, path)
+        finally:
+            if os.path.exists(temporary):
+                os.unlink(temporary)
+    if isinstance(values, ConfigSnapshot):
+        values.original = copy.deepcopy(dict(values))
+    return ConfigSnapshot(latest)