// Copyright 2021 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// Package sysapi provides helper functions for performing various tasks on
// a system. All policy_manager code should use functions in this package instead of Go's
// built-in equivalents in order to allow testing on non-COS machines.
package sysapi

import "os"

// APIHandler interface defines the supported functions.
type APIHandler interface {
	// ReadFile reads the named file and returns the content.
	ReadFile(name string) (content []byte, err error)

	// WriteFile writes the given content to the named file with the
	// supplied permission.
	WriteFile(name string, content []byte, perm os.FileMode) error

	// AtomicWriteFile atomically writes a file.
	AtomicWriteFile(name string, data []byte, perm os.FileMode) error

	// RunCommand returns the stdout and stderr produced by running the
	// named program with the given arguments.
	RunCommand(name string, arg ...string) (stdout, stderr []byte, err error)

	// MkdirAll creates a directory named path, along with any necessary
	// parents, and returns nil, or else returns an error. The permission
	// bits perm are used for all directories that MkdirAll creates. If path
	// is already a directory, MkdirAll does nothing and returns nil.
	MkdirAll(path string, perm os.FileMode) error

	// FileExists checks if the named file exists.
	FileExists(path string) bool

	// GetUnixTimestamp returns the current UNIX timestamp.
	GetUnixTimestamp() int64
}