package octez-internal-libs

  1. Overview
  2. Docs
package octez-internal-libs
Legend:
Page
Library
Module
Module type
Parameter
Class
Class type
Source

Source file snapshot.ml

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
(*
 * Copyright (c) 2018-2022 Tarides <contact@tarides.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *)

open! Import
open Snapshot_intf

let rm_index path =
  let path_index = Filename.concat path "index" in
  Sys.readdir path_index
  |> Array.iter (fun name -> Unix.unlink (Filename.concat path_index name));
  Unix.rmdir path_index;
  Unix.rmdir path

module Make (Args : Args) = struct
  module Hashes = Irmin.Hash.Set.Make (Args.Hash)
  open Args
  module Inode_pack = Inode.Pack
  module Pack_index = Pack_index.Make (Hash)

  let pp_hash = Irmin.Type.pp Hash.t
  let pp_key = Irmin.Type.pp Inode_pack.Key.t
  let pp_kind = Irmin.Type.pp Pack_value.Kind.t
  let pp_snapshot = Irmin.Type.pp Inode.Snapshot.inode_t

  module Export = struct
    module Value_unit = struct
      type t = unit [@@deriving irmin]

      let encode _ = ""
      let encoded_size = 0
      let decode _ _ = ()
    end

    module Index =
      Index_unix.Make (Pack_index.Key) (Value_unit) (Index.Cache.Unbounded)

    type t = {
      fm : Fm.t;
      dispatcher : Dispatcher.t;
      log_size : int;
      inode_pack : read Inode_pack.t;
      contents_pack : read Contents_pack.t;
    }

    let v config contents_pack inode_pack =
      (* In order to read from the pack files, we need to open at least two
         files: suffix and control. We just open the file manager for
         simplicity. *)
      let fm = Fm.open_ro config |> Fm.Errs.raise_if_error in
      let dispatcher = Dispatcher.v fm |> Fm.Errs.raise_if_error in
      let log_size = Conf.index_log_size config in
      { fm; dispatcher; log_size; inode_pack; contents_pack }

    let close t = Fm.close t.fm

    let key_of_hash hash t =
      Inode_pack.index_direct_with_kind t hash |> Option.get

    let length_of_hash hash t =
      let key, _ = key_of_hash hash t in
      match Pack_key.inspect key with
      | Indexed _ ->
          (* This case cannot happen, as [key_of_hash] converts an
             indexed key to a direct one. *)
          assert false
      | Direct { length; _ } -> length

    let io_read_and_decode_entry_prefix ~off t =
      let entry_prefix : Inode_pack.Entry_prefix.t =
        Inode_pack.read_and_decode_entry_prefix ~off t.dispatcher
      in
      let length =
        match Inode_pack.Entry_prefix.total_entry_length entry_prefix with
        | Some length -> length
        | None ->
            (* If the length is not on disk, the object is in index. *)
            length_of_hash entry_prefix.hash t.inode_pack
      in
      let key = Pack_key.v_direct ~offset:off ~length entry_prefix.hash in
      (key, entry_prefix.kind)

    (* Get the childrens offsets and then read their keys at that offset. *)
    let decode_children_offsets ~off ~len t =
      let buf = Bytes.create len in
      let _ = Dispatcher.read_exn t.dispatcher ~off ~len buf in
      let entry_of_offset offset =
        [%log.debug "key_of_offset: %a" Int63.pp offset];
        io_read_and_decode_entry_prefix ~off:offset t
      in
      let entry_of_hash hash = key_of_hash hash t.inode_pack in
      (* Bytes.unsafe_to_string usage: buf is created locally, uniquely owned; we assume
         Dispatcher.read_exn returns unique ownership; then call to Bytes.unsafe_to_string
         gives up unique ownership of buf. This is safe. *)
      Inode.Raw.decode_children_offsets ~entry_of_offset ~entry_of_hash
        (Bytes.unsafe_to_string buf) (* safe: see comment above *)
        (ref 0)

    type visit = { visited : Hash.t -> bool; set_visit : Hash.t -> unit }

    let iter t v f_contents f_inodes (root_key, root_kind) =
      let total_visited = ref 0 in
      let set_visit h =
        incr total_visited;
        v.set_visit h
      in
      let rec aux (key, kind) =
        match Pack_key.inspect key with
        | Indexed _ ->
            (* This case cannot happen:
               - either the root key is indexed, in which case it converted to a
               direct key just before the call to [aux];
               - or one of the children of a node is indexed, in which case
               [Inode.Raw.decode_children_offsets] converts it to a direct key
               before the call to [aux]. *)
            assert false
        | Direct { length; offset; hash; _ } ->
            if v.visited hash then Lwt.return_unit
            else (
              set_visit hash;
              [%log.debug "visit hash: %a, %a" pp_hash hash pp_kind kind];
              (* [unsafe_find] decodes the values based on their kind, we need
                 to detect the type in order to call the correspoding
                 [unsafe_find].*)
              match kind with
              | Contents -> (
                  let value =
                    Contents_pack.unsafe_find ~check_integrity:false
                      t.contents_pack key
                  in
                  match value with
                  | None ->
                      Fmt.failwith "contents not found in store. Key: %a "
                        pp_key key
                  | Some value ->
                      let snapshot_blob = value in
                      f_contents snapshot_blob)
              | Inode_v1_unstable | Inode_v1_stable | Inode_v2_root
              | Inode_v2_nonroot -> (
                  let children =
                    decode_children_offsets ~off:offset ~len:length t
                  in
                  let* () = Lwt_list.iter_s (fun key -> aux key) children in
                  let value =
                    Inode_pack.unsafe_find ~check_integrity:false t.inode_pack
                      key
                  in
                  match value with
                  | None ->
                      Fmt.failwith "node not found in store. Key: %a " pp_key
                        key
                  | Some value ->
                      let snapshot_inode = Inode.to_snapshot value in
                      [%log.debug
                        "iter inode snapshot: %a" pp_snapshot snapshot_inode];
                      f_inodes snapshot_inode)
              | Commit_v1 | Commit_v2 ->
                  (* The traversal starts with a node, it never iters over
                     commits. *)
                  assert false
              | Dangling_parent_commit -> assert false)
      in
      (* In case the root node of a tree is indexed, we need to convert it to a
         direct key first. *)
      let root_key =
        match Pack_key.inspect root_key with
        | Indexed hash -> key_of_hash hash t.inode_pack |> fst
        | Direct _ -> root_key
      in
      let* () = aux (root_key, root_kind) in
      Lwt.return !total_visited

    let run_in_memory t f_contents f_inodes root_key =
      [%log.info "iter in memory"];
      let visited_hash = Hashes.create ~initial_slots:100_000 () in
      let visited h = Hashes.mem visited_hash h in
      let set_visit h =
        match Hashes.add visited_hash h with
        | `Duplicate ->
            Fmt.failwith "should not visit hash twice. Hash: %a " pp_hash h
        | `Ok -> ()
      in
      iter t { visited; set_visit } f_contents f_inodes root_key

    let run_on_disk path t f_contents f_inodes root_key =
      [%log.info "iter on disk"];
      let index =
        Index.v ~fresh:true ~readonly:false ~log_size:t.log_size path
      in
      let visited h = Index.mem index h in
      let set_visit h =
        if visited h then
          Fmt.failwith "Should not visit hash twice. Hash: %a " pp_hash h
        else Index.replace index h ()
      in
      let* total = iter t { visited; set_visit } f_contents f_inodes root_key in
      Index.close index;
      rm_index path;
      Lwt.return total

    let run ?on_disk =
      match on_disk with
      | None -> run_in_memory
      | Some (`Path path) -> run_on_disk path
  end

  module Import = struct
    module Value = struct
      type t = int63 * int [@@deriving irmin]

      let encoded_size = (64 / 8) + (32 / 8)

      let encode ((off, len) : t) =
        let buf = Bytes.create encoded_size in
        Bytes.set_int64_be buf 0 (Int63.to_int64 off);
        Bytes.set_int32_be buf 8 (Int32.of_int len);
        (* Bytes.unsafe_to_string usage: buf is local, uniquely owned; we assume the
           Bytes.set... functions return unique ownership; then Bytes.unsafe_to_string
           gives up unique ownership of buf to get shared ownership of the resulting
           string, which is then returned. buf is no longer accessible. This is safe. *)
        Bytes.unsafe_to_string buf

      let decode s pos : t =
        (* Bytes.unsafe_of_string usage: s is shared; buf is shared (we cannot mutate it);
           we assume Bytes.get_... functions need shared ownership only. This usage is
           safe. *)
        let buf = Bytes.unsafe_of_string s in
        let off = Bytes.get_int64_be buf pos |> Int63.of_int64 in
        let len = Bytes.get_int32_be buf (pos + 8) |> Int32.to_int in
        (off, len)
    end

    module Index =
      Index_unix.Make (Pack_index.Key) (Value) (Index.Cache.Unbounded)

    type path = string

    type t = {
      inode_pack : read Inode_pack.t;
      contents_pack : read Contents_pack.t;
      visited : Hash.t -> Hash.t Pack_key.t;
      set_visit : Hash.t -> Hash.t Pack_key.t -> unit;
      index : (path * Index.t) option;
    }

    let save_contents t b : Hash.t Pack_key.t Lwt.t =
      let* key =
        Contents_pack.batch t.contents_pack (fun writer ->
            Contents_pack.add writer b)
      in
      let hash = Inode.Key.to_hash key in
      t.set_visit hash key;
      Lwt.return key

    let save_inodes t i : Hash.t Pack_key.t Lwt.t =
      let inode = Inode.of_snapshot t.inode_pack ~index:t.visited i in
      let key = Inode.save ~allow_non_root:true t.inode_pack inode in
      let hash = Inode.Key.to_hash key in
      t.set_visit hash key;
      Lwt.return key

    let hash_not_found h =
      Fmt.failwith
        "You are trying to save to the backend an inode that contains pointers \
         to objects unknown to the backend. Hash: %a"
        pp_hash h

    let save_reuse_index inodes =
      [%log.info "save reuse index "];
      (* objects are added to index by [save_contents] and [save_inodes]
         functions. *)
      let set_visit _ _ = () in
      let visited h =
        match Inode_pack.index_direct inodes h with
        | Some x -> x
        | None -> hash_not_found h
      in
      (set_visit, visited, None)

    let save_in_memory () =
      [%log.info "save in memory"];
      let tbl : (Hash.t, Hash.t Pack_key.t) Hashtbl.t = Hashtbl.create 10 in
      let set_visit h k = Hashtbl.add tbl h k in
      let visited h =
        match Hashtbl.find_opt tbl h with
        | Some x -> x
        | None -> hash_not_found h
      in
      (set_visit, visited, None)

    let save_on_disk log_size path =
      (* Make sure we are not reusing the same index as irmin-pack. *)
      let path = path ^ "_tmp" in
      [%log.info "save on disk: %s" path];
      let index = Index.v ~fresh:true ~readonly:false ~log_size path in

      let set_visit h k =
        let offset, length =
          match Pack_key.inspect k with
          | Direct { offset; length; _ } -> (offset, length)
          | Indexed _ ->
              (* Visited objects have direct keys. *)
              assert false
        in
        Index.replace index h (offset, length)
      in
      let visited h =
        try
          let offset, length = Index.find index h in
          let key = Pack_key.v_direct ~offset ~length h in
          key
        with Not_found -> hash_not_found h
      in
      (set_visit, visited, Some (path, index))

    let v ?on_disk log_size contents_pack inode_pack =
      let set_visit, visited, index =
        match on_disk with
        | None -> save_in_memory ()
        | Some (`Path path) -> save_on_disk log_size path
        | Some `Reuse -> save_reuse_index inode_pack
      in
      { inode_pack; contents_pack; visited; set_visit; index }

    let close t =
      Option.iter
        (fun (path, index) ->
          Index.close index;
          rm_index path)
        t.index
  end
end
OCaml

Innovation. Community. Security.

GitHub Discord Twitter Peertube RSS
About
Changelog Releases Industrial Users Academic Users Why OCaml
Ecosystem
Packages Community Events OCaml Planet Jobs
Resources
Install OCaml Get Started Platform Tools Language Manual Standard Library API Books Exercises Papers OCaml Playground Logo
Policies
Carbon Footprint Governance Privacy Code of Conduct