luke
/
sbt
mirror of https://github.com/sbt/sbt.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

add documention for FileFunction.cached

This commit is contained in:
Tim Harper 2016-02-09 02:10:03 -07:00
parent 49e801070f
commit fe0c3df36e
1 changed files with 18 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
cache/tracking/src/main/scala/sbt/Tracked.scala vendored
View File

@ -231,6 +231,24 @@ class Difference(val cache: File, val style: FilesInfo.Style, val defineClean: B
object FileFunction {
type UpdateFunction = (ChangeReport[File], ChangeReport[File]) => Set[File]
/**
Generic change-detection helper used to help build / artifact generation /
etc. steps detect whether or not they need to run. Returns a function whose
input is a Set of input files, and subsequently executes the action function
(which does the actual work: compiles, generates resources, etc.), returning
a Set of output files that it generated.
The input file and resulting output file state is cached in
cacheBaseDirectory. On each invocation, the state of the input and output
files from the previous run is compared against the cache, as is the set of
input files. If a change in file state / input files set is detected, the
action function is re-executed.
@param cacheBaseDirectory The folder in which to store
@param inStyle The strategy by which to detect state change in the input files from the previous run
@param outStyle The strategy by which to detect state change in the output files from the previous run
@param action The work function, which receives a list of input files and returns a list of output files
*/
def cached(cacheBaseDirectory: File, inStyle: FilesInfo.Style = FilesInfo.lastModified, outStyle: FilesInfo.Style = FilesInfo.exists)(action: Set[File] => Set[File]): Set[File] => Set[File] =
cached(cacheBaseDirectory)(inStyle, outStyle)((in, out) => action(in.checked))