// Copyright 2025 The Dawn & Tint Authors
//
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// modification, are permitted provided that the following conditions are met:
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// 1. Redistributions of source code must retain the above copyright notice, this
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//    this software without specific prior written permission.
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package fileutils

import (
	"path/filepath"

	"dawn.googlesource.com/dawn/tools/src/oswrapper"
)

func CreateMemMapOSWrapperWithFakeDawnRoot() (oswrapper.MemMapOSWrapper, error) {
	wrapper := oswrapper.CreateMemMapOSWrapper()
	err := SetUpFakeDawnRoot(wrapper)
	if err != nil {
		return wrapper, err
	}
	return wrapper, nil
}

func SetUpFakeDawnRoot(fsWriter oswrapper.MemMapOSWrapper) error {
	thisDir := ThisDir()
	dawnRoot := filepath.Dir(filepath.Dir(filepath.Dir(thisDir)))
	err := fsWriter.MkdirAll(dawnRoot, 0o666)
	if err != nil {
		return err
	}

	deps := filepath.Join(dawnRoot, "DEPS")
	f, err := fsWriter.Create(deps)
	if err != nil {
		return err
	}
	f.Close()
	return nil
}