1	import Base
2	import bend-kit-bytes@0.3.2.0/bytes.bend as StorageBytes
3	import 0x6c54b2522c2258baf6f58d2b970c3902/files.bend as PackedFiles
4	
5	# Audited host effects (spec §3.3). Thin syscall wrappers with .c + .js
6	# twins and matching intended semantics. No laws — validated empirically.
7	
8	# Read at most 1 MiB as packed words. Short reads are valid progress; zero is EOF.
9	def read_words(
10	  file: File,
11	  max: U32
12	) ->
13	  IO(File & Result<&1, &1, U32 & String, U32 & Array<U32>>):
14	  PackedFiles.read.words(file, max)
15	
16	# Write all bytes from a packed word array, retaining the file handle on errors.
17	def write_words(
18	  file: File,
19	  len: U32,
20	  words: Array<U32>
21	) ->
22	  IO(File & Result<&1, &1, U32 & String, Unit>):
23	  PackedFiles.write.words(file, len, words)
24	
25	def read_bytes.wrap(
26	  result: Result<&1, &1, U32 & String, U32 & Array<U32>>
27	) ->
28	  Result<&1, &1, U32 & String, StorageBytes.Bytes>:
29	  match result:
30	    case Fail{err}:
31	      Fail{err}
32	    case Done{(len, words)}:
33	      Done{StorageBytes.Bytes{len, words}}
34	
35	def read_bytes.pair(
36	  pair: File & Result<&1, &1, U32 & String, U32 & Array<U32>>
37	) ->
38	  File & Result<&1, &1, U32 & String, StorageBytes.Bytes>:
39	  match pair:
40	    case (handle, result):
41	      (handle, read_bytes.wrap(result))
42	
43	# Read one bounded packed chunk; nonempty short reads are not EOF.
44	def read_bytes(
45	  file: File,
46	  max: U32
47	) ->
48	  IO(File & Result<&1, &1, U32 & String, StorageBytes.Bytes>):
49	  do IO<File & Result<&1, &1, U32 & String, StorageBytes.Bytes>>:
50	    pair : File & Result<&1, &1, U32 & String, U32 & Array<U32>> <- read_words(file, max)
51	    return read_bytes.pair(pair)
52	
53	# Write the significant bytes of a packed buffer through the pinned host effect.
54	def write_bytes(
55	  file: File,
56	  bytes: StorageBytes.Bytes
57	) ->
58	  IO(File & Result<&1, &1, U32 & String, Unit>):
59	  StorageBytes.Bytes{len, buf} = bytes
60	  write_words(file, len, buf)
61	
62	# Sync file contents to stable storage.
63	def fsync(path: String) -> IO(Result<&1, &1, U32 & String, Unit>):
64	  import "./effs/fsync.c"
65	  import "./effs/fsync.js"
66	
67	# Handle truncate in the filesystem effects.
68	def truncate(path: String, offset: Nat) -> IO(Result<&1, &1, U32 & String, Unit>):
69	  import "./effs/truncate.c"
70	  import "./effs/truncate.js"
71	
72	# Atomically rename a filesystem path.
73	def rename(old: String, new: String) -> IO(Result<&1, &1, U32 & String, Unit>):
74	  import "./effs/rename.c"
75	  import "./effs/rename.js"
76	
77	# Remove a file or empty directory.
78	def remove(path: String) -> IO(Result<&1, &1, U32 & String, Unit>):
79	  import "./effs/remove.c"
80	  import "./effs/remove.js"
81	
82	# Return the number of entries available through the indexed directory API.
83	def read_dir_count(path: String) -> IO(Result<&1, &1, U32 & String, Nat>):
84	  import "./effs/read_dir.c"
85	  import "./effs/read_dir.js"
86	
87	# Fetch one directory entry by index.
88	def read_dir_at(path: String, idx: Nat) -> IO(Result<&1, &1, U32 & String, String>):
89	  import "./effs/read_dir.c"
90	  import "./effs/read_dir.js"
91	
92	# Create one directory.
93	def make_dir(path: String) -> IO(Result<&1, &1, U32 & String, Unit>):
94	  import "./effs/make_dir.c"
95	  import "./effs/make_dir.js"
96	
97	# Set POSIX permission bits.
98	def chmod(path: String, bits: U32) -> IO(Result<&1, &1, U32 & String, Unit>):
99	  import "./effs/chmod.c"
100	  import "./effs/chmod.js"
101	
102	# Check whether a filesystem path exists.
103	def exists(path: String) -> IO(Result<&1, &1, U32 & String, Bool>):
104	  import "./effs/exists.c"
105	  import "./effs/exists.js"
106	
107	# Read-only byte size for Bend-side accounting (no shell wc needed).
108	def file_size(path: String) -> IO(Result<&1, &1, U32 & String, Nat>):
109	  import "./effs/file_size.c"
110	  import "./effs/file_size.js"
111	
112	# Pure accumulator step (leaf: matches structurally, never recurses).
113	# Past-end fetches answer "" (SNil{}), which is skipped.
114	def grab_name(nm: String, acc: List<String>) -> List<String>:
115	  match nm:
116	    case SNil{}:
117	      acc
118	    case SCon{_, _}:
119	      Con{nm, acc}
120	
121	# Fuel-bounded sweep 0..count-1. Startup-only use (spec §10 below): the
122	# directory is stable during recovery, so count-then-fetch is exact.
123	def read_go(fuel: Nat, +path: String, +idx: Nat, acc: List<String>) -> IO(List<String>):
124	  match fuel:
125	    case 0n:
126	      IO.pure(List<String>, List.reverse(&1, String, acc))
127	    case 1n+f:
128	      do IO<List<String>>:
129	        nm : String <- IO.try(String, read_dir_at(path, idx))
130	        read_go(f, path, Nat.add(idx, 1n), grab_name(nm, acc))
131	
132	# List directory names using the bounded count-then-fetch host API.
133	def read_dir(+path: String) -> IO(Result<&1, &1, U32 & String, List<String>>):
134	  do IO<Result<&1, &1, U32 & String, List<String>>>:
135	    n : Nat <- IO.try(Nat, read_dir_count(path))
136	    names : List<String> <- read_go(Nat.add(n, 1n), path, 0n, Nil{})
137	    return Done{names}