files.bend source
files.bend on the hub · documented module
# POSIX paths plus directory and metadata effects. Source: https://github.com/paymog/bend-kit/tree/main/filesimport Baseimport bend-kit-bytes@0.3.1.0/bytes.bend as Bytes# The path.* defs are pure and lexical: they never touch the disk.# The effects are thin OS calls; each failure is (errno, text).# import ./files/files.bend as Fsdef path.is_absolute(p: String) -> Bool: String.starts_with(p, "/")def path.join.rel(bare: Bool, a: String, b: String) -> String: match bare: case True{}: a ++ b case False{}: a ++ "/" ++ bdef path.join.if(abs: Bool, +a: String, b: String) -> String: match abs: case True{}: b case False{}: path.join.rel(String.is_empty(a) || String.ends_with(a, "/"), a, b)# b when b is absolute; otherwise b under a.def path.join(a: String, +b: String) -> String: path.join.if(path.is_absolute(b), a, b)def path.norm.pop.if(up: Bool, h: String, t: List<&2, String>) -> List<&2, String>: match up: case True{}: ".." <> (h <> t) case False{}: t# A ".." above the root is dropped; above a relative start it is kept.def path.norm.pop(stack: List<&2, String>, abs: Bool) -> List<&2, String>: match stack: case Nil{}: Bool.pick(List<&2, String>, abs, Nil{}, [".."]) case Con{+h, t}: path.norm.pop.if(String.eq(h, ".."), h, t)def path.norm.step( skip: Bool, up: Bool, s: String, stack: List<&2, String>, abs: Bool) -> List<&2, String>: match skip: case True{}: stack case False{}: match up: case True{}: path.norm.pop(stack, abs) case False{}: s <> stack# The kept segments, last first.def path.norm.go(segs: List<&2, String>, stack: List<&2, String>, +abs: Bool) -> List<&2, String>: match segs: case Nil{}: stack case Con{+s, t}: path.norm.go(t, path.norm.step(String.eq(s, "") || String.eq(s, "."), String.eq(s, ".."), s, stack, abs), abs)def path.norm.fin(abs: Bool, body: String) -> String: match abs: case True{}: "/" ++ body case False{}: match body: case SNil{}: "." case SCon{h, t}: SCon{h, t}# Drops empty and "." segments and resolves "..", as POSIX normpath does# (RFC 3986 §5.2.4 for paths), but always to one leading "/".def path.normalize(+p: String) -> String: +abs = path.is_absolute(p) path.norm.fin(abs, String.join(List.reverse(&2, String, path.norm.go(String.split(p, '/'), Nil{}, abs)), "/"))def path.parent(p: String) -> String: +n = path.normalize(p) path.norm.fin(path.is_absolute(n), String.join(List.reverse(&2, String, List.tail(&2, String, List.reverse(&2, String, String.split(n, '/')))), "/"))def path.file_name.fin(m: Maybe<&2, String>) -> String: match m: case None{}: "" case Some{+s}: Bool.pick(String, String.eq(s, "."), "", s)# The last segment of the normalized path; "" for "/" and ".".def path.file_name(p: String) -> String: path.file_name.fin(List.last(&2, String, String.split(path.normalize(p), '/')))def path.extension.fin(bare: Bool, ext: String) -> String: match bare: case True{}: "" case False{}: extdef path.extension.go(rev: List<&2, String>) -> String: match rev: case Nil{}: "" case Con{ext, Nil{}}: "" case Con{ext, Con{prev, rest}}: path.extension.fin(String.is_empty(prev) && List.is_empty(&2, String, rest), ext)# The text after the file name's last ".", without the dot. A leading dot# does not start one: ".bashrc" has none.def path.extension(p: String) -> String: path.extension.go(List.reverse(&2, String, String.split(path.file_name(p), '.')))type FileType is Data: Regular{} Directory{} Other{}# mtime is whole seconds since the Unix epoch. size and mtime wrap at 2^32.type Info is Data: Info{kind: FileType, size: U32, mtime: U32}# Entry names, NUL-separated, in the order the OS gives them.def list_dir.raw(path: String) -> IO(Result<&1, &1, U32 & String, String>): import "./effs/files.c" import "./effs/files.js"# (kind, size, mtime); kind 0 is a regular file, 1 a directory, 2 other.# Symbolic links are followed.def stat.raw(path: String) -> IO(Result<&1, &1, U32 & String, U32 & U32 & U32>): import "./effs/files.c" import "./effs/files.js"def mkdir(path: String) -> IO(Result<&1, &1, U32 & String, Unit>): import "./effs/files.c" import "./effs/files.js"# Removes a file or an empty directory.def remove(path: String) -> IO(Result<&1, &1, U32 & String, Unit>): import "./effs/files.c" import "./effs/files.js"def rename(from: String, to: String) -> IO(Result<&1, &1, U32 & String, Unit>): import "./effs/files.c" import "./effs/files.js"# Creates a new, empty, private directory under the system temp dir.def temp_dir() -> IO(Result<&1, &1, U32 & String, String>): import "./effs/files.c" import "./effs/files.js"# A successful zero-length read is EOF (or max = 0). Reads at most 1 MiB# per call; a short read is not necessarily EOF. Errors retain the File.def read.words(file: File, max: U32) -> IO(File & Result<&1, &1, U32 & String, U32 & Array<U32>>): import "./effs/files.c" import "./effs/files.js"def read_bytes.wrap(result: Result<&1, &1, U32 & String, U32 & Array<U32>>) -> Result<&1, &1, U32 & String, Bytes.Bytes>: match result: case Fail{err}: Fail{err} case Done{(len, words)}: Done{Bytes.Bytes{len, words}}def read_bytes.pair(pair: File & Result<&1, &1, U32 & String, U32 & Array<U32>>) -> File & Result<&1, &1, U32 & String, Bytes.Bytes>: match pair: case (handle, result): (handle, read_bytes.wrap(result))# The existing Bytes layout, without an octet List or String.def read_bytes(file: File, max: U32) -> IO(File & Result<&1, &1, U32 & String, Bytes.Bytes>): do IO<File & Result<&1, &1, U32 & String, Bytes.Bytes>>: pair : File & Result<&1, &1, U32 & String, U32 & Array<U32>> <- read.words(file, max) return read_bytes.pair(pair)# Writes the entire buffer or fails. Errors retain the File; writes before# an error are not rolled back. A len beyond the word array fails EINVAL.def write.words(file: File, len: U32, words: Array<U32>) -> IO(File & Result<&1, &1, U32 & String, Unit>): import "./effs/files.c" import "./effs/files.js"def write_bytes(file: File, data: Bytes.Bytes) -> IO(File & Result<&1, &1, U32 & String, Unit>): Bytes.Bytes{len, buf} = data write.words(file, len, buf)def list_dir.fin(r: Result<&1, &1, U32 & String, String>) -> Result<&1, &1, U32 & String, List<&2, String>>: match r: case Fail{e}: Fail{e} case Done{s}: Done{List.sort(~String, ~String.is_le, List.filter(~String, ~(n => Bool.not(String.is_empty(n))), String.split(s, Chr{0})))}# Entry names, without "." and "..", sorted.def list_dir(path: String) -> IO(Result<&1, &1, U32 & String, List<&2, String>>): do IO<Result<&1, &1, U32 & String, List<&2, String>>>: r : Result<&1, &1, U32 & String, String> <- list_dir.raw(path) return list_dir.fin(r)def stat.kind(+k: U32) -> FileType: Bool.pick(FileType, U32.is_eq(k, 0), Regular{}, Bool.pick(FileType, U32.is_eq(k, 1), Directory{}, Other{}))def stat.fin(r: Result<&1, &1, U32 & String, U32 & U32 & U32>) -> Result<&1, &1, U32 & String, Info>: match r: case Fail{e}: Fail{e} case Done{(k, size, mtime)}: Done{Info{stat.kind(k), size, mtime}}def stat(path: String) -> IO(Result<&1, &1, U32 & String, Info>): do IO<Result<&1, &1, U32 & String, Info>>: r : Result<&1, &1, U32 & String, U32 & U32 & U32> <- stat.raw(path) return stat.fin(r)def exists(path: String) -> IO(Bool): do IO<Bool>: r : Result<&1, &1, U32 & String, U32 & U32 & U32> <- stat.raw(path) return Result.is_done(&1, &1, U32 & String, U32 & U32 & U32, r)def mkdir_all.dir(r: Result<&1, &1, U32 & String, Info>) -> Result<&1, &1, U32 & String, Unit>: match r: case Fail{e}: Fail{e} case Done{Info{Directory{}, size, mtime}}: Done{Unit{}} case Done{i}: Fail{(17, "File exists")}def mkdir_all.fail(exists: Bool, e: U32 & String, k: IO(Result<&1, &1, U32 & String, Unit>)) -> IO(Result<&1, &1, U32 & String, Unit>): match exists: case True{}: k case False{}: IO.pure(Result<&1, &1, U32 & String, Unit>, Fail{e})def mkdir_all.step(r: Result<&1, &1, U32 & String, Unit>, k: IO(Result<&1, &1, U32 & String, Unit>)) -> IO(Result<&1, &1, U32 & String, Unit>): match r: case Fail{(+code, text)}: mkdir_all.fail(U32.is_eq(code, 17), (code, text), k) case Done{u}: kdef mkdir_all.go(segs: List<&2, String>, +at: String) -> IO(Result<&1, &1, U32 & String, Unit>): match segs: case Nil{}: do IO<Result<&1, &1, U32 & String, Unit>>: r : Result<&1, &1, U32 & String, Info> <- stat(at) return mkdir_all.dir(r) case Con{s, t}: +next = path.join(at, s) do IO<Result<&1, &1, U32 & String, Unit>>: r : Result<&1, &1, U32 & String, Unit> <- mkdir(next) mkdir_all.step(r, mkdir_all.go(t, next))# Creates the directory and any missing parents. Succeeds when it is# already a directory; fails if a component is not a directory.def mkdir_all(+path: String) -> IO(Result<&1, &1, U32 & String, Unit>): mkdir_all.go( List.filter(~String, ~(n => Bool.not(String.eq(n, ""))), String.split(path, '/')), Bool.pick(String, path.is_absolute(path), "/", "."))