Module B0_memo

Build memoizer


type t

The type for memoizers. Provides a context to issue memoizable operations.

Tool spawns

TODO explain better how this all works and try to simplify. If the path given to Tool.t is not made of a single path segment it is not search in the environmet and it is the duty of the client to ensure it gets ready at some point. Either by a direct call to ready_file or by another file write.

module Tool : sig ... end

Command line tools.

module Env : sig ... end

Memo environment lookups.

type tool_lookup = t -> B0_std.Cmd.tool -> (B0_std.Fpath.t, string) Stdlib.result B0_std.Fut.t

The type for tool lookups. Given a command line tool specification returns a file path to the tool executable or an error message mentioning the tool if it cannot be found.

val tool_lookup_of_os_env : ?sep:string -> ?var:string -> B0_std.Os.Env.t -> tool_lookup

env_tool_lookup ~sep ~var env is a tool lookup that gets the value of the var variable in env treats it as a sep separated search path and uses the result to lookup with B0_std.Os.Cmd.get with the memo's win_exe. var defaults to PATH and sep to B0_std.Fpath.search_path_sep.

type cmd

The type for memoized tool invocations.

type tool

The type for memoized tools.

val tool : t -> Tool.t -> B0_std.Cmd.t -> cmd

tool m t is tool t memoized. Use the resulting function to spawn the tool with the given arguments.

val tool_opt : t -> Tool.t -> (B0_std.Cmd.t -> cmd) option B0_std.Fut.t

tool_opt m t is like tool, except None is returned if the tool cannot be found. y

val spawn : t -> ?stamp:string -> ?reads:B0_std.Fpath.t list -> ?writes:B0_std.Fpath.t list -> ?env:B0_std.Os.Env.t -> ?cwd:B0_std.Fpath.t -> ?stdin:B0_std.Fpath.t -> ?stdout:B0_zero.Op.Spawn.stdo -> ?stderr:B0_zero.Op.Spawn.stdo -> ?success_exits:B0_zero.Op.Spawn.success_exits -> ?post_exec:(B0_zero.Op.t -> unit) -> ?k:(B0_zero.Op.t -> int -> unit) -> cmd -> unit

spawn m ~reads ~writes ~env ~cwd ~stdin ~stdout ~stderr ~success_exits cmd spawns cmd once reads files are ready and makes files writes ready if the spawn succeeds and the file exists. The rest of the arguments are:

  • stdin reads input from the given file. If unspecified reads from the standard input of the program running the build. Warning. The file is not automatically added to reads, this allows for example to use B0_std.Fpath.null.
  • stdout and stderr, the redirections for the standard outputs of the command, see B0_zero.Op.Spawn.stdo. Path to files are created if needed. Warning. File redirections are not automatically added to writes; this allows for example to use B0_std.Fpath.null.
  • success_exits the exit codes that determine if the build operation is successful (defaults to 0, use [] to always succeed)
  • env, environment variables added to the build environment. This overrides environment variables read by the tool in the build environment except for forced one. It also allows to specify enovironment that may not be mentioned by the running tool's environment specification.
  • cwd the current working directory. Default is the memo's cwd. In general it's better to avoid using relative file paths and tweaking the cwd. Construct make your paths absolute and invocations independent from the cwd.
  • post_exec, if specified is called with the build operation after it has been executed or revived. If it was executed this is called before the operation gets recorded. It can be used to define the reads and writes of the operation if they are difficult to find out before hand. Do not access m in that function.
  • k, if specified a function invoked once the spawn has succesfully executed with the operation and the exit code.
  • stamp is used for caching if two spawns diff only in their stamp they will cache to different keys. This can be used to memoize tool whose outputs may not entirely depend on the environment, the cli stamp and the the content of read files.

Note. If the tool spawn acts on a sort of "main" file (e.g. a source file) it should be specified as the first element of reads, this is interpreted specially by certain build tracer.

val spawn' : t -> ?stamp:string -> ?reads:B0_std.Fpath.t list -> writes_root:B0_std.Fpath.t -> ?writes:(B0_zero.Op.t -> B0_std.Fpath.t list) -> ?env:B0_std.Os.Env.t -> ?cwd:B0_std.Fpath.t -> ?stdin:B0_std.Fpath.t -> ?stdout:B0_zero.Op.Spawn.stdo -> ?stderr:B0_zero.Op.Spawn.stdo -> ?success_exits:B0_zero.Op.Spawn.success_exits -> ?k:(B0_zero.Op.t -> int -> unit) -> cmd -> unit

spawn' is like spawn except the actual file paths written by the spawn need not be determined before the spawn. Only the root directory of writes need to be specified via writes_root. After the spawn executes the writes can be determined via the writes function, the returned paths must be absolute and be prefixed by writes_root (defaults to recursively list all the files rooted in writes_root).

Procedures and failing them

val run_proc : t -> (unit -> unit B0_std.Fut.t) -> unit

run_proc m proc calls proc () and handles any failure. This also catches non-asynchronous uncaught exceptions and turns them into `Fail notification operations.

val fail : t -> ('a, Stdlib.Format.formatter, unit, 'b) Stdlib.format4 -> 'a

fail m fmt ... fails the procedure via a notify operation.

val fail_if_error : t -> ('a, string) Stdlib.result -> 'a

fail_if_error m r is v if r is Ok v and fail m "%s" e if r is Error _.

Files and directories

val ready_file : t -> B0_std.Fpath.t -> unit

read_file m p declares path p to be ready, that is exists and is up-to-date in b. This is typically used with source files and files external to the build like installed libraries.

val ready_files : t -> B0_std.Fpath.t list -> unit

ready_files m ps is List.iter (ready_files m) ps.

val read : t -> B0_std.Fpath.t -> string B0_std.Fut.t

read m file k is a future that determines with the contents s of file file when it becomes ready in m.

val write : t -> ?stamp:string -> ?reads:B0_std.Fpath.t list -> ?mode:int -> B0_std.Fpath.t -> (unit -> (string, string) Stdlib.result) -> unit

write m ~reads file w writes file with data w () and mode mode (defaults to 0o644) when reads are ready. w's result must only depend on reads, mode and stamp (defaults to "") and should not perform other side effects on the file system.

val copy : t -> ?mode:int -> ?linenum:int -> B0_std.Fpath.t -> dst:B0_std.Fpath.t -> unit

copy m ~mode ?linenum src ~dst copies file src to dst with mode mode (defaults to 0o644) when src is ready. If linenum is specified, the following line number directive is prependend in dst to the contents of src:

#line $(linenum) "$(src)"
val copy_to_dir : t -> ?mode:int -> ?linenum:int -> ?src_root:B0_std.Fpath.t -> B0_std.Fpath.t -> dir:B0_std.Fpath.t -> B0_std.Fpath.t

copy_to_dir src dir is copy src ~dst with dst as Fpath.reroot ~src_root ~dst_root:dst src and src_root defaulting to Fpath.parent src. The function returns the destination file.

val mkdir : t -> ?mode:int -> B0_std.Fpath.t -> unit B0_std.Fut.t

mkdir m dir p is a future that determines with () when the directory path p has been created with mode mode (defaults to 0o755). The behaviour with respect to file permission of intermediate path segments matches B0_std.Os.Dir.create.

val delete : t -> B0_std.Fpath.t -> unit B0_std.Fut.t

delete m p is a future that determines with () when path p is deleted (trashed in fact) and free to reuse.

val wait_files : t -> B0_std.Fpath.t list -> unit B0_std.Fut.t

wait_files m files is a future that deterines with () when all files are ready in m. FIXME Unclear whether we really want this, but somehow it's part of the primitives.

Activity marks

Activity marks are just identifiers used for UI purposes to watermark the activity – notably build operations – occuring in the memo.

val mark : t -> string

mark m is m's mark.

val with_mark : t -> string -> t

mark m mark is m but operations performed on m are marked by mark.


XXX This needs a bit of reviewing.

type notify_kind = [
  1. | `Fail
  2. | `Warn
  3. | `Start
  4. | `End
  5. | `Info
val notify : ?k:(unit -> unit) -> t -> notify_kind -> ('a, Stdlib.Format.formatter, unit, unit) Stdlib.format4 -> 'a

notify m kind msg is a notification msg of kind kind. Note that a `Fail notification will entail an an has_failures on the memo, see also fail and fail_if_error.

val notify_if_error : t -> notify_kind -> use:'a -> ('a, string) Stdlib.result -> 'a

notify_if_error m kind ~use r is v if r is Ok v. If r is Error e, a notification of kind kind is added to m and use is returned. Note that a `Fail notification will entail an has_failures on the memo, see also fail and fail_if_error.


type feedback = [
  1. | `Op_complete of B0_zero.Op.t

The type for memoizer feedback.

val make_zero : ?clock:B0_std.Os.Mtime.counter -> ?cpu_clock:B0_std.Os.Cpu.Time.counter -> feedback:(feedback -> unit) -> cwd:B0_std.Fpath.t -> ?win_exe:bool -> ?tool_lookup:tool_lookup -> ?env:B0_std.Os.Env.t -> ?forced_env_vars:Tool.env_vars -> B0_zero.Guard.t -> B0_zero.Reviver.t -> B0_zero.Exec.t -> (t, string) Stdlib.result
val make : ?hash_fun:(module B0_std.Hash.T) -> ?win_exe:bool -> ?tool_lookup:tool_lookup -> ?env:B0_std.Os.Env.t -> ?forced_env_vars:Tool.env_vars -> ?cwd:B0_std.Fpath.t -> ?jobs:int -> ?feedback:([ feedback | ] -> unit) -> cache_dir:B0_std.Fpath.t -> trash_dir:B0_std.Fpath.t -> unit -> (t, string) Stdlib.result

make is a simpler make_zero

val with_feedback : t -> (feedback -> unit) -> t

with_feedback m feedback is m with feedback replaced by feedback.

Low-level operations

val delete_trash : block:bool -> t -> (unit, string) Stdlib.result

delete_trash ~block m is B0_zero.Trash.delete ~block (trash m).

val hash_string : t -> string -> B0_std.Hash.t

hash_string m s is B0_zero.Reviver.hash_string (reviver m) s.

val hash_file : t -> B0_std.Fpath.t -> (B0_std.Hash.t, string) Stdlib.result

hash_file m f is B0_zero.Reviver.hash_file (reviver m) f. Note that these file hashes operations are memoized.

val stir : block:bool -> t -> unit

stir ~block m runs the memoizer a bit. If block is true blocks until the memoizer is stuck with no operation to execute.

val status : t -> (unit, B0_zero.Op.aggregate_error) Stdlib.result

status m looks for aggregate errors in m in ops m, see B0_zero.Op.aggregate_error for details.

Usually called after a blocking stir to check everything executed as expected. The function itself has no effect more operations can be on m afterwards. If you are only interested in checking if a failure occured in the memo has_failures is faster.

val timestamp : t -> B0_std.Mtime.Span.t

timestamp m gets a clock time stamp.


val clock : t -> B0_std.Os.Mtime.counter

clock m is m's clock.

val cpu_clock : t -> B0_std.Os.Cpu.Time.counter

cpu_clock m is m's cpu clock.

val env : t -> B0_std.Os.Env.t

env m is the environment of m. The environment read by the tools' declared environment variables.

val exec : t -> B0_zero.Exec.t

exec m is m's executors.

val forced_env_vars : t -> Tool.env_vars

forced_env_vars m are the forced environment variables of m. These variables are put in the stamped environment of any tool despite what it declares to access.

val guard : t -> B0_zero.Guard.t

guard m is m's guard.

val has_failures : t -> bool

has_failures m is true iff at least one operation has failed.

val ops : t -> B0_zero.Op.t list

ops m is the list of operations that were submitted to the memoizer

val reviver : t -> B0_zero.Reviver.t

reviver m is m's reviver.

val tool_lookup : t -> tool_lookup

tool_lookup m is m's tool lookup function.

val trash : t -> B0_zero.Trash.t

trash m is m's trash.

val win_exe : t -> bool

win_exe m is true if we spawn windows executables. This affects tool lookups. Defaults to Sys.win32.