package b0

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Module type
Class type

Build memoizer.

A memoizer ties together and environment, an operation cache, a guard and an executor.

type t

The type for memoizers. This ties together an environment, a guard, an operation cache and an executor.

Tool lookup

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 feedback = [
  1. | `Miss_tool of Tool.t * string
  2. | `Op_complete of B000.Op.t

The type for memoizer feedback. FIXME remove `Miss_tool now that we have notify operations.

val create : ?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.t -> B000.Guard.t -> B000.Reviver.t -> B000.Exec.t -> t
val memo : ?hash_fun:(module B0_std.Hash.T) -> ?win_exe:bool -> ?tool_lookup:tool_lookup -> ?env:B0_std.Os.Env.t -> ?cwd:B0_std.Fpath.t -> ?cache_dir:B0_std.Fpath.t -> ?trash_dir:B0_std.Fpath.t -> ?jobs:int -> ?feedback:([ feedback | ] -> unit) -> unit -> (t, string) Stdlib.result

memo is a simpler create

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 win_exe : t -> bool

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

val tool_lookup : t -> tool_lookup

tool_lookup m is m's tool lookup function.

val env : t -> Env.t

env m is m's environment.

val reviver : t -> B000.Reviver.t

reviver m is m's reviver.

val guard : t -> B000.Guard.t

guard m is m's guard.

val exec : t -> B000.Exec.t

exec m is m's executors.

val trash : t -> B000.Trash.t

trash m is m's trash.

val has_failures : t -> bool

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

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

hash_string m s is B000.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 B000.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, B000.Op.aggregate_error) Stdlib.result

status m looks for aggregate errors in m in ops m, see B000.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 delete_trash : block:bool -> t -> (unit, string) Stdlib.result

delete_trash ~block m is B000.Trash.delete ~block (trash m).

val ops : t -> B000.Op.t list

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

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.


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

run 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 _.


XXX This needs a bit of reviewing.

val notify : ?k:(unit -> unit) -> t -> [ `Fail | `Warn | `Start | `End | `Info ] -> ('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 -> [ `Fail | `Warn | `Start | `End | `Info ] -> 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.

Files and directories

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

ready 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 (e.g. installed libraries).

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 and stamp (defaults to "").

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

Memoizing tool spawns

TODO. Can't we simplify the cmd/tool/tool_lookup dance ?.

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.

TODO explain better how this all works. 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 file_ready or by another file write.

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:B000.Op.Spawn.stdo -> ?stderr:B000.Op.Spawn.stdo -> ?success_exits:B000.Op.Spawn.success_exits -> ?post_exec:(B000.Op.t -> unit) -> ?k:(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 B000.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 environment 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 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:(B000.Op.t -> B0_std.Fpath.t list) -> ?env:B0_std.Os.Env.t -> ?cwd:B0_std.Fpath.t -> ?stdin:B0_std.Fpath.t -> ?stdout:B000.Op.Spawn.stdo -> ?stderr:B000.Op.Spawn.stdo -> ?success_exits:B000.Op.Spawn.success_exits -> ?k:(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 rootet in writes_root).


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