// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// This wrapper uses syscall.Flock to prevent concurrent adb commands,
// so for now it only builds on platforms that support that system call.
// TODO(#33974): use a more portable library for file locking.

//go:build darwin || dragonfly || freebsd || illumos || linux || netbsd || openbsd

Otherwise, each read of a single-word-sized or sub-word-sized memory location
must observe a value actually written to that location (perhaps by a concurrent executing goroutine)
and not yet overwritten.
These implementation constraints make Go more like Java or JavaScript,
in that most races have a limited number of outcomes,

	if err != nil {
		return
	}
	return f.headerOffset + bodyOffset, nil
}

// Open returns a [ReadCloser] that provides access to the [File]'s contents.
// Multiple files may be read concurrently.
func (f *File) Open() (io.ReadCloser, error) {
	bodyOffset, err := f.findBodyOffset()
	if err != nil {
		return nil, err
	}
	if strings.HasSuffix(f.Name, "/") {

	// works, but only when running one binary at a time.
	// Use a file lock to make sure only one wrapper is running at a time.
	//
	// The lock file is never deleted, to avoid concurrent locks on distinct
	// files with the same path.
	lockName := filepath.Join(os.TempDir(), "go_ios_exec-"+deviceID+".lock")
	lock, err = os.OpenFile(lockName, os.O_CREATE|os.O_RDONLY, 0666)
	if err != nil {

}

var listCache sync.Map // map[string]listImports, keyed by contextName

// listSem is a semaphore restricting concurrent invocations of 'go list'. 'go
// list' has its own internal concurrency, so we use a hard-coded constant (to
// allow the I/O-intensive phases of 'go list' to overlap) instead of scaling
// all the way up to GOMAXPROCS.
var listSem = make(chan semToken, 2)