How can I process only files that have changed? - ant

Question

At the moment I'm doing this:
<delete dir="${RSA.dir}/file1" />
<copy todir="${RSA.dir}/file1" >
<fileset dir="${CLEARCASE.dir}/file1" />
</copy>
and repeating the same thing for other files - but it takes a long time.
I only want to delete and copy files that have been updated, with their modified date in clearcase later than that in RSA.
How can I do that?

Answer 1

Look into the sync task.
If you want to do it based on file contents, and ignore the timestamp, I think this macro will do that:
<macrodef name="mirror" description="Copy files only if different; remove files that do not exist in dir. This works similiar to robocopy /MIR." >
<attribute name="dir"/>
<attribute name="todir"/>
<sequential>
<copy overwrite="true" todir="#{todir}">
<fileset dir="#{dir}">
<different targetdir="${todir}"/>
</fileset>
</copy>
<delete includeemptydirs="true">
<fileset dir="#todir}">
<present targetdir="${dir}" present="srconly"/>
</fileset>
</delete>
</sequential>
</macrodef>

Answer 2

You need to use a selector on a FileSet. Something like this:
<fileset dir="${your.working.dir}/src/main" includes="**/*.java">
<different targetdir="${clean.clearcase.checkout}/src/main"
ignoreFileTimes="false"
ignoreContents="true" />
</fileset>
That compares your working dir to a clean checkout you have elsewhere, and returns the files whose last modified times have changed. You can use the fileset as the argument for a <delete> or a <copy>.