Filter files by checking if their modification times or MD5 checksums have changed.
Usage
filter_newfile(files)
filter_timestamp(files)
filter_md5sum(files, db = "blogdown/md5sum.txt")Details
The function filter_newfile() returns paths of source files that do
not have corresponding output files, e.g., an .Rmd file that doesn't
have the .html output file.
The function filter_timestamp() compares the modification time of an
Rmd file with that of its output file, and returns the path of a file if it
is newer than its output file by N seconds (or if the output file does
not exist), where N is obtained from the R global option
blogdown.time_diff. By default, N = 0. You may change it via
options(), e.g., options(blogdown.time_diff = 5) means an Rmd
file will be returned when its modification time at least 5 seconds newer
than its output file's modification time.
The function filter_md5sum() reads the MD5 checksums of files from a
database (a tab-separated text file), and returns the files of which the
checksums have changed. If the database does not exist, write the checksums
of files to it, otherwise update the checksums after the changed files have
been identified. When a file is modified, its MD5 checksum is very likely to
change.
These functions can be used to determine which Rmd files to be rebuilt in a
blogdown website. See build_site() for more information.