package irmin-pack
Install
Dune Dependency
Authors
Maintainers
Sources
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doc/irmin-pack.unix/Irmin_pack_unix/Io/Unix/index.html
Module Io.Unix
Source
Low level IO abstraction. A typical implementation is unix. This abstraction is meant to be dead simple. Not a lot of documentation is required.
It is not resistant to race condictions. There should not be concurrent modifications of the files.
These functions are essentially invoking the underlying functions from Unix
directly; there is no buffering for example.
Errors
An abstract error type that contains the IO-backend specific errors. (e.g. Unix.error
)
type read_error = [
| `Io_misc of misc_error
| `Read_out_of_bounds
| `Closed
| `Invalid_argument
]
type mkdir_error = [
| `Io_misc of misc_error
| `File_exists of string
| `No_such_file_or_directory
| `Invalid_parent_directory
]
Safe Functions
None of the functions in this section raise exceptions. They may however perform effects that are always continued.
Life Cycle
Write Functions
write_string t ~off s
writes s
at offset
in t
.
fsync t
persists to the file system the effects of previous create
or write.
Read Functions
read_to_string t ~off ~len
are the len
bytes of t
at off
.
read_to_string t
is the contents full contents of the file.
The individual pages are not guaranteed to be read atomically.
read_size t
is the number of bytes of the file handled by t
.
This function is expensive in the unix implementation because it performs syscalls.
MISC.
Unsafe Functions
These functions are equivalents to exising safe ones, but using exceptions instead of the result monad for performances reasons.
read_exn t ~off ~len b
reads the len
bytes of t
at off
to b
.
Raises Errors.Pack_error
and Errors.RO_not_allowed
.
Also raises backend-specific exceptions (e.g. Unix.Unix_error
for the unix backend).
write_exn t ~off ~len b
writes the first len
bytes pf b
to t
at offset off
.
Raises Errors.Pack_error
and Errors.RO_not_allowed
.
Also raises backend-specific exceptions (e.g. Unix.Unix_error
for the unix backend).