1d5fd64383
The global daemon registry (~/.beads/registry.json) could be corrupted when multiple daemons from different workspaces wrote simultaneously. Changes: - Add file locking (flock) for cross-process synchronization - Use atomic writes (temp file + rename) to prevent partial writes - Keep entire read-modify-write cycle under single lock - Add FlockExclusiveBlocking and FlockUnlock to lockfile package This prevents race conditions that caused JSON corruption like `]]`. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
70 lines
1.5 KiB
Go
70 lines
1.5 KiB
Go
//go:build windows
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package lockfile
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import (
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"errors"
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"os"
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"syscall"
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"golang.org/x/sys/windows"
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)
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var errDaemonLocked = errors.New("daemon lock already held by another process")
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// flockExclusive acquires an exclusive non-blocking lock on the file using LockFileEx
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func flockExclusive(f *os.File) error {
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// LOCKFILE_EXCLUSIVE_LOCK (2) | LOCKFILE_FAIL_IMMEDIATELY (1) = 3
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const flags = windows.LOCKFILE_EXCLUSIVE_LOCK | windows.LOCKFILE_FAIL_IMMEDIATELY
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// Create overlapped structure for the entire file
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ol := &windows.Overlapped{}
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// Lock entire file (0xFFFFFFFF, 0xFFFFFFFF = maximum range)
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err := windows.LockFileEx(
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windows.Handle(f.Fd()),
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flags,
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0, // reserved
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0xFFFFFFFF, // number of bytes to lock (low)
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0xFFFFFFFF, // number of bytes to lock (high)
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ol,
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)
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if err == windows.ERROR_LOCK_VIOLATION || err == syscall.EWOULDBLOCK {
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return errDaemonLocked
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}
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return err
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}
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// FlockExclusiveBlocking acquires an exclusive blocking lock on the file.
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// This will wait until the lock is available.
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func FlockExclusiveBlocking(f *os.File) error {
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// LOCKFILE_EXCLUSIVE_LOCK only (no FAIL_IMMEDIATELY = blocking)
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const flags = windows.LOCKFILE_EXCLUSIVE_LOCK
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ol := &windows.Overlapped{}
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return windows.LockFileEx(
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windows.Handle(f.Fd()),
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flags,
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0,
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0xFFFFFFFF,
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0xFFFFFFFF,
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ol,
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)
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}
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// FlockUnlock releases a lock on the file.
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func FlockUnlock(f *os.File) error {
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ol := &windows.Overlapped{}
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return windows.UnlockFileEx(
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windows.Handle(f.Fd()),
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0,
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0xFFFFFFFF,
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0xFFFFFFFF,
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ol,
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)
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}
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