ScriptInfo: improve behavior of script identifiers

Script IDs are now of the form "script:${name}" for named scripts,
"script:${path}" for unnamed scripts with a file path given, and
"script:<${hex}>" where "${hex}" is a hexidecimal hash code of the
script contents when it has neither name nor path.

In this way, script IDs should hopefully always be unique, except
in the case where they are intended to collide -- e.g., to
dynamically replace one version of a script with another.

Author: ctrueden

src/main/java/org/scijava/script/ScriptInfo.java

@@ -359,7 +359,12 @@ public void setContext(final Context context) {
 
 	@Override
 	public String getIdentifier() {
-		return "script:" + (path == null ? "<inline>" : path);
+		final String name = getName();
+		final String prefix = "script:";
+		if (name != null) return prefix + name;
+		if (path != null) return prefix + path;
+		if (script != null) return prefix + "<" + DigestUtils.bestHex(script) + ">";
+		return prefix + "<unknown>";
 	}
 
 	// -- Locatable methods --

src/test/java/org/scijava/script/ScriptInfoTest.java

@@ -95,6 +95,35 @@ public void tearDown() {
 
 	// -- Tests --
 
+	/** Tests script identifiers. */
+	@Test
+	public void testGetIdentifier() {
+		final String name = "strategerize";
+
+		final String namedPath = "victory.bsizes";
+		final String named = "" + //
+			"#@script(name = '" + name + "')\n" + //
+			"zxywvutsrqponmlkjihgfdcba\n";
+
+		final String unnamedPath = "alphabet.bsizes";
+		final String unnamed = "" + //
+			"ABCDEFGHIJKLMNOPQRSTUVWXYZ\n" + //
+			"0123456789\n";
+
+		// Test named, with explicit path.
+		assertEquals("script:" + name, id(namedPath, named));
+
+		// Test named, and no path given.
+		assertEquals("script:" + name, id(null, named));
+
+		// Test unnamed, with explicit path.
+		assertEquals("script:" + unnamedPath, id(unnamedPath, unnamed));
+
+		// Test unnamed, and no path given.
+		final String hex = DigestUtils.bestHex(unnamed);
+		assertEquals("script:<" + hex + ">", id(null, unnamed));
+	}
+
 	/** Tests whether new-style parameter syntax are parsed correctly. */
 	@Test
 	public void testNewStyle() throws Exception {
@@ -323,6 +352,15 @@ public void testReaderSanity() throws Exception {
 		assertEquals("Readers are not independent.", reader1.read(), reader2.read());
 	}
 
+	// -- Helper methods --
+
+	private String id(final String path, final String script) {
+		final ScriptInfo info = //
+			new ScriptInfo(context, path, new StringReader(script));
+		info.inputs(); // NB: Force parameter parsing.
+		return info.getIdentifier();
+	}
+
 	private void assertItem(final String name, final Class<?> type,
 		final String label, final ItemIO ioType, final boolean required,
 		final boolean persist, final String persistKey, final String style,