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* Copyright by the contributors to the Dafny Project
* SPDX-License-Identifier: MIT
*******************************************************************************/
// RUN: %verify "%s"
include "../Wrappers.dfy"
/**
* This module provides basic file I/O operations: reading and writing bytes from/to a file.
* The provided API is intentionally limited in scope and will be expanded later.
*
* Where the API accepts file paths as strings, there are some limitations.
* File paths containing only ASCII characters work identically across languages and platforms;
* non-ASCII Unicode codepoints may cause different language- or platform-specific behavior.
*
* File path symbols including . and .. are allowed.
*/
module {:options "-functionSyntax:4"} FileIO {
import opened Wrappers
export provides ReadBytesFromFile, WriteBytesToFile, Wrappers
/*
* Public API
*/
/**
* Attempts to read all bytes from the file at the given file path.
* If an error occurs, a `Result.Failure` value is returned containing an implementation-specific
* error message (which may also contain a stack trace).
*
* NOTE: See the module description for limitations on the path argument.
*/
method ReadBytesFromFile(path: string) returns (res: Result<seq<bv8>, string>) {
var isError, bytesRead, errorMsg := INTERNAL_ReadBytesFromFile(path);
return if isError then Failure(errorMsg) else Success(bytesRead);
}
/**
* Attempts to write the given bytes to the file at the given file path,
* creating nonexistent parent directories as necessary.
* If an error occurs, a `Result.Failure` value is returned containing an implementation-specific
* error message (which may also contain a stack trace).
*
* NOTE: See the module description for limitations on the path argument.
*/
method WriteBytesToFile(path: string, bytes: seq<bv8>) returns (res: Result<(), string>)
{
var isError, errorMsg := INTERNAL_WriteBytesToFile(path, bytes);
return if isError then Failure(errorMsg) else Success(());
}
/*
* Private API - these are intentionally not exported from the module and should not be used elsewhere
*/
method
{:extern "DafnyLibraries.FileIO", "INTERNAL_ReadBytesFromFile"}
INTERNAL_ReadBytesFromFile(path: string)
returns (isError: bool, bytesRead: seq<bv8>, errorMsg: string)
method
{:extern "DafnyLibraries.FileIO", "INTERNAL_WriteBytesToFile"}
INTERNAL_WriteBytesToFile(path: string, bytes: seq<bv8>)
returns (isError: bool, errorMsg: string)
}
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