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57 lines
2.3 KiB
OCaml
57 lines
2.3 KiB
OCaml
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(*
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copyright (c) 2013, simon cruanes
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all rights reserved.
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redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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redistributions of source code must retain the above copyright notice, this
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list of conditions and the following disclaimer. redistributions in binary
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form must reproduce the above copyright notice, this list of conditions and the
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following disclaimer in the documentation and/or other materials provided with
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the distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*)
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(** {1 Serialize Bencode on disk with persistency guarantees}
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This module provides an append-only interface to some file, with
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synchronized access and fsync() called after every write.
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It needs {b Extunix} to compile (needs fsync).
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*)
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type t
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(** Handle to a file on which we can append values atomically *)
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val open_out : ?lock:string -> string -> t
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(** Open the given file for appending values. Creates the file
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if it doesn't exist.
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@param lock, if provided, is the name of the lock file used. By default,
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the file that is provided for writing is also used for locking.
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@raise Unix.Unix_error if some IO error occurs. *)
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val close_out : t -> unit
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(** Close the file descriptor *)
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val write : t -> Bencode.t -> unit
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(** Write "atomically" a value to the end of the file *)
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type 'a result =
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| Ok of 'a
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| Error of string
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val read : ?lock:string -> string -> 'a -> ('a -> Bencode.t -> 'a) -> 'a result
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(** Fold on values serialized in the given file.
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@param lock see {!open_out}.
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@raise Unix.Unix_error if some IO error occurs. *)
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