Add recursive variant of Config.getNames() methods

These methods allow to find all configuration entry names for a given
section or section/subsection searching recursively through all base
configurations of the given configuration.

These methods are needed to calculate the names for the effective
configuration of a git repository which combines the configuration entry
names found in the repository, global and system configuration files

Bug: 396659
Change-Id: Ie3731b5e877f8686aadad3f1a46b2e583ad3b7c6
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ConfigTest.java

@@ -519,6 +519,31 @@ public class ConfigTest {
 		assertFalse(itr.hasNext());
 	}
 
+	@Test
+	public void test_ReadNamesInSectionRecursive()
+			throws ConfigInvalidException {
+		String baseConfigString = "[core]\n" + "logAllRefUpdates = true\n";
+		String configString = "[core]\n" + "repositoryFormatVersion = 0\n"
+				+ "filemode = false\n";
+		final Config c = parse(configString, parse(baseConfigString));
+		Set<String> names = c.getNames("core", true);
+		assertEquals("Core section size", 3, names.size());
+		assertTrue("Core section should contain \"filemode\"",
+				names.contains("filemode"));
+		assertTrue("Core section should contain \"repositoryFormatVersion\"",
+				names.contains("repositoryFormatVersion"));
+		assertTrue("Core section should contain \"logAllRefUpdates\"",
+				names.contains("logAllRefUpdates"));
+		assertTrue("Core section should contain \"logallrefupdates\"",
+				names.contains("logallrefupdates"));
+
+		Iterator<String> itr = names.iterator();
+		assertEquals("filemode", itr.next());
+		assertEquals("repositoryFormatVersion", itr.next());
+		assertEquals("logAllRefUpdates", itr.next());
+		assertFalse(itr.hasNext());
+	}
+
 	@Test
 	public void test010_readNamesInSubSection() throws ConfigInvalidException {
 		String configString = "[a \"sub1\"]\n"//
@@ -540,6 +565,30 @@ public class ConfigTest {
 		assertTrue("Subsection should contain \"b\"", names.contains("b"));
 	}
 
+	@Test
+	public void readNamesInSubSectionRecursive() throws ConfigInvalidException {
+		String baseConfigString = "[a \"sub1\"]\n"//
+				+ "x = 0\n" //
+				+ "y = false\n"//
+				+ "[a \"sub2\"]\n"//
+				+ "A=0\n";//
+		String configString = "[a \"sub1\"]\n"//
+				+ "z = true\n"//
+				+ "[a \"sub2\"]\n"//
+				+ "B=1\n";
+		final Config c = parse(configString, parse(baseConfigString));
+		Set<String> names = c.getNames("a", "sub1", true);
+		assertEquals("Subsection size", 3, names.size());
+		assertTrue("Subsection should contain \"x\"", names.contains("x"));
+		assertTrue("Subsection should contain \"y\"", names.contains("y"));
+		assertTrue("Subsection should contain \"z\"", names.contains("z"));
+		names = c.getNames("a", "sub2", true);
+		assertEquals("Subsection size", 2, names.size());
+		assertTrue("Subsection should contain \"A\"", names.contains("A"));
+		assertTrue("Subsection should contain \"a\"", names.contains("a"));
+		assertTrue("Subsection should contain \"B\"", names.contains("B"));
+	}
+
 	@Test
 	public void testQuotingForSubSectionNames() {
 		String resultPattern = "[testsection \"{0}\"]\n\ttestname = testvalue\n";
@@ -584,7 +633,12 @@ public class ConfigTest {
 
 	private static Config parse(final String content)
 			throws ConfigInvalidException {
-		final Config c = new Config(null);
+		return parse(content, null);
+	}
+
+	private static Config parse(final String content, Config baseConfig)
+			throws ConfigInvalidException {
+		final Config c = new Config(baseConfig);
 		c.fromText(content);
 		return c;
 	}

org.eclipse.jgit/src/org/eclipse/jgit/lib/Config.java

@@ -527,6 +527,33 @@ public class Config {
 		return getState().getNames(section, subsection);
 	}
 
+	/**
+	 * @param section
+	 *            the section
+	 * @param recursive
+	 *            if {@code true} recursively adds the names defined in all base
+	 *            configurations
+	 * @return the list of names defined for this section
+	 */
+	public Set<String> getNames(String section, boolean recursive) {
+		return getState().getNames(section, null, recursive);
+	}
+
+	/**
+	 * @param section
+	 *            the section
+	 * @param subsection
+	 *            the subsection
+	 * @param recursive
+	 *            if {@code true} recursively adds the names defined in all base
+	 *            configurations
+	 * @return the list of names defined for this subsection
+	 */
+	public Set<String> getNames(String section, String subsection,
+			boolean recursive) {
+		return getState().getNames(section, subsection, recursive);
+	}
+
 	/**
 	 * Obtain a handle to a parsed set of configuration values.
 	 *

org.eclipse.jgit/src/org/eclipse/jgit/lib/ConfigSnapshot.java

@@ -97,6 +97,16 @@ class ConfigSnapshot {
 	}
 
 	Set<String> getNames(String section, String subsection) {
+		return getNames(section, subsection, false);
+	}
+
+	Set<String> getNames(String section, String subsection, boolean recursive) {
+		Map<String, String> m = getNamesInternal(section, subsection, recursive);
+		return new CaseFoldingSet(m);
+	}
+
+	private Map<String, String> getNamesInternal(String section,
+			String subsection, boolean recursive) {
 		List<ConfigLine> s = sorted();
 		int idx = find(s, section, subsection, ""); //$NON-NLS-1$
 		if (idx < 0)
@@ -113,7 +123,9 @@ class ConfigSnapshot {
 			if (!m.containsKey(l))
 				m.put(l, e.name);
 		}
-		return new CaseFoldingSet(m);
+		if (recursive && baseState != null)
+			m.putAll(baseState.getNamesInternal(section, subsection, recursive));
+		return m;
 	}
 
 	String[] get(String section, String subsection, String name) {