Update registryTool task to better handle command line arguments (#273)

* Update registryTool task to better handle command line arguments

Tokens are delimited by pipes and can be escaped. If we use -args
directly, we will not be able to escape the delimiter, if both the
double and single quotes happen to be present in the arguments.

See:

https://docs.gradle.org/current/javadoc/org/gradle/api/tasks/JavaExec.html#setArgsString-java.lang.String-

core/build.gradle

@@ -592,11 +592,40 @@ task findGoldenImages(type: JavaExec) {
   args arguments
 }
 
-// To run the nomulus tool:
+// To run the nomulus tool with these command line tokens:
-// gradle registryTool --args="foo --bar"
+// "--foo", "bar baz", "--qux=quz"
+//   gradle registryTool --args="--foo 'bar baz' --qux=quz"
+// or:
+//   gradle registryTool --PtoolArgs="--foo|bar baz|--qux=quz"
+// Note that the delimiting pipe can be backslash escaped if it is part of a
+// parameter.
 task registryTool(type: JavaExec) {
   classpath = sourceSets.main.runtimeClasspath
   main = 'google.registry.tools.RegistryTool'
+
+  // If "-PtoolArgs=..." is present in the command line, use it to set the args,
+  // otherwise use the default flag, which is "--args" to set the args.
+  doFirst {
+    def toolArgs = rootProject.findProperty("toolArgs")
+    if (toolArgs != null) {
+      def delimiter = '|'
+      toolArgs += delimiter
+      def argsList = []
+      def currArg = ''
+      for (def i = 0; i < toolArgs.length(); i++) {
+        def currChar = toolArgs[i]
+        if (currChar != delimiter) {
+          currArg += currChar
+        } else if (i != 0 && toolArgs[i - 1] == '\\') {
+          currArg = currArg.substring(0, currArg.length() - 1) + currChar
+        } else {
+          argsList.add(currArg)
+          currArg = ''
+        }
+      }
+      args = argsList
+    }
+  }
 }
 
 task generateGoldenImages(type: Test) {