Reworked/improved auto-update build/publish tools.

Instead of working on a single 'auto-update' branch,
that needed to be rebased from master branch's HEAD,
we create an orphan branch named after master:HEAD
containing on the update file.

This allows us to keep/delete updates on a per-commit
basis and shows which commit each update is based upon.

Added loads more checking.

tools/build-auto-update.sh

@@ -0,0 +1,81 @@
+#!/usr/bin/env bash
+
+set -e
+
+# Check we are within a git repo
+git_dir=$( git rev-parse --show-toplevel )
+if [ -z "${git_dir}" ]; then
+	echo "Cannot determine top-level directory for git repo"
+	exit 1
+fi
+
+# Change to git top-level
+cd ${git_dir}
+
+# Check we are in 'master' branch
+branch_name=$( git symbolic-ref -q HEAD )
+branch_name=${branch_name##refs/heads/}
+echo "Current git branch: ${branch_name}"
+if [ "${branch_name}" != "master" ]; then
+	echo "Unexpected current branch '${branch_name}' - expecting 'master'"
+	exit 1
+fi
+
+# Extract short-form commit hash
+short_hash=$( git rev-parse --short HEAD )
+if [ -z "${short_hash}" ]; then
+	echo "Unable to extract short-form current commit hash"
+	exit 1
+fi
+echo "HEAD commit is: ${short_hash}"
+
+# Check there are no uncommitted changes
+uncommitted=$( git status --short --untracked-files=no )
+if [ ! -z "${uncommitted}" ]; then
+	echo "Cannot continue due to uncommitted files:"
+	echo "${uncommitted}"
+	exit 1
+fi
+
+# Determine project name
+project=$( perl -n -e 'if (m/<artifactId>(\w+)<.artifactId>/) { print $1; exit }' pom.xml $)
+if [ -z "${project}" ]; then
+	echo "Unable to determine project name from pom.xml?"
+	exit 1
+fi
+
+# Actually rebuild JAR
+echo "Building ${project} JAR..."
+mvn clean package 1>/tmp/${project}-mvn-build.log 2>&1
+if [ "$?" != "0" -o ! -r target/${project}*.jar ]; then
+	echo "Maven build failed. For details, see /tmp/${project}-mvn-build.log"
+	exit 1
+fi
+
+# Convert packaged JAR to XORed update form
+echo "Building ${project}.update..."
+java -cp target/${project}*.jar org.qortal.XorUpdate target/${project}*.jar ${project}.update
+if [ "$?" != "0" ]; then
+	echo "Failed to create XORed auto-update JAR"
+	exit 1
+fi
+
+# Create auto-update branch from this commit
+update_branch=auto-update-${short_hash}
+
+if git show-ref --quiet --verify refs/heads/${update_branch}; then
+	echo "Existing auto-update branch based on this commit (${short_hash}) - deleting..."
+	git branch --delete --force ${update_branch}
+fi
+
+echo "Checking out new auto-update branch based on this commit (${short_hash})..."
+git checkout --orphan ${update_branch}
+git rm --cached -fr . 1>/dev/null
+
+git add ${project}.update
+
+git commit --message "XORed, auto-update JAR based on commit ${short_hash}"
+git push --set-upstream origin --force-with-lease ${update_branch}
+
+echo "Changing back to 'master' branch"
+git checkout --force master