Ant and git integration.

build.xml

<?xml version="1.0" encoding='utf-8'?>
<project name="test" default="version">
    <taskdef resource="net/sf/antcontrib/antcontrib.properties"/>

    <available file=".git" type="dir" property="git.present"/>
    <available file="version.properties" type="file" property="version.present"/>

    <target name="versiongit" if="git.present">
        <exec executable="git" outputproperty="git.commit" failonerror="true">
            <arg value="rev-parse"/>
            <arg value="HEAD"/>
        </exec>
        <exec executable="git" outputproperty="temp.git.tag" failonerror="false"
            resultproperty="git.describeresult">
            <arg value="describe"/>
            <arg value="--abbrev=0"/>
        </exec>
        <if>
            <equals arg1="${git.describeresult}" arg2="0"/>
            <then>
                <exec executable="git" outputproperty="git.tag.commit">
                    <arg value="rev-parse"/>
                    <arg value="${temp.git.tag}"/>
                </exec>
                <if>
                    <equals arg1="${git.commit}" arg2="${git.tag.commit}"/>
                    <then>
                        <property name="temp.git.version" value="${git.tag}"/>
                    </then>
                    <else>
                        <property name="temp.git.version" value="${git.tag}-${git.commit}"/>
                    </else>
                </if>
            </then>
            <else>
                <property name="git.tag" value="none"/>
                <property name="temp.git.version" value="${git.commit}"/>
            </else>
        </if>
        <exec executable="git" resultproperty="git.uncommited" failonerror="false">
            <arg value="diff-index"/>
            <arg value="--quiet"/>
            <arg value="--cached"/>
            <arg value="HEAD"/>
        </exec>
        <exec executable="git" resultproperty="git.untracked" failonerror="false">
            <arg value="diff-files"/>
            <arg value="--quiet"/>
        </exec>
        <if>
            <not>
                <and>
                    <equals arg1="${git.uncommited}" arg2="0"/>
                    <equals arg1="${git.untracked}" arg2="0"/>
                </and>
            </not>
            <then>
                <buildnumber/>
                <property name="git.version" value="${temp.git.version}-b${build.number}"/>
            </then>
            <else>
                <delete file="build.number"/>
                <property name="build.number" value="0"/>
                <property name="git.version" value="${temp.git.version}"/>
            </else>
        </if>
        <propertyfile file="version.properties" comment="Project version information">
            <entry key="git.commit" value="${git.commit}"/>
            <entry key="git.tag" value="${git.tag}"/>
            <entry key="git.version" value="${git.version}"/>
            <entry key="build.number" value="${build.number}"/>
        </propertyfile>
    </target>
    <target name="versionproperties" unless="git.present">
        <fail unless="version.present" message="No version information found!"/>
        <loadproperties srcFile="version.properties"/>
        <fail unless="git.commit" message="No git commit information found!"/>
        <fail unless="git.tag" message="No git tag information found!"/>
        <fail unless="git.version" message="No git version information found!"/>
    </target>
    <target name="version" depends="versiongit,versionproperties">
        <echo>Version: ${git.version}</echo>
        <echo>Tag:     ${git.tag}</echo>
        <echo>Commit:  ${git.commit}</echo>
        <echo>Build:   ${build.number}</echo>
    </target>
</project>