Cache user global and system-wide git configurations

So far the git configuration and the system wide git configuration were
always reloaded when jgit accessed these global configuration files to
access global configuration options which are not in the context of a
single git repository. Cache these configurations in SystemReader and
only reload them if their file metadata observed using FileSnapshot
indicates a modification.

Change-Id: I092fe11a5d95f1c5799273cacfc7a415d0b7786c
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

2 files changed, 47 insertions, 33 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/CloneCommandTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/CloneCommandTest.java
index 0d7009dca4..613ca5ce95 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/CloneCommandTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/CloneCommandTest.java
@@ -68,9 +68,9 @@ import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.lib.StoredConfig;
 import org.eclipse.jgit.revwalk.RevBlob;
 import org.eclipse.jgit.revwalk.RevCommit;
-import org.eclipse.jgit.storage.file.FileBasedConfig;
 import org.eclipse.jgit.submodule.SubmoduleStatus;
 import org.eclipse.jgit.submodule.SubmoduleStatusType;
 import org.eclipse.jgit.submodule.SubmoduleWalk;
@@ -633,8 +633,8 @@ public class CloneCommandTest extends RepositoryTestCase {
 				ConfigConstants.CONFIG_BRANCH_SECTION, "test",
 				ConfigConstants.CONFIG_KEY_REBASE, null));
 
-		FileBasedConfig userConfig = SystemReader.getInstance().openUserConfig(
-				null, git.getRepository().getFS());
+		StoredConfig userConfig = SystemReader.getInstance()
+				.getUserConfig();
 		userConfig.setString(ConfigConstants.CONFIG_BRANCH_SECTION, null,
 				ConfigConstants.CONFIG_KEY_AUTOSETUPREBASE,
 				ConfigConstants.CONFIG_KEY_ALWAYS);
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/FS_POSIXTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/FS_POSIXTest.java
index 9683f93e69..87349a25a4 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/FS_POSIXTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/FS_POSIXTest.java
@@ -43,48 +43,63 @@
 
 package org.eclipse.jgit.util;
 
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import org.eclipse.jgit.junit.MockSystemReader;
 import org.eclipse.jgit.lib.ConfigConstants;
 import org.eclipse.jgit.storage.file.FileBasedConfig;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
-import org.mockito.Mockito;
-
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.when;
 
 public class FS_POSIXTest {
 	private SystemReader originalSystemReaderInstance;
 
-	private FileBasedConfig mockSystemConfig;
+	private FileBasedConfig systemConfig;
+
+	private FileBasedConfig userConfig;
 
-	private FileBasedConfig mockUserConfig;
+	private Path tmp;
 
 	@Before
 	public void setUp() throws Exception {
-		SystemReader systemReader = Mockito.mock(SystemReader.class);
+		tmp = Files.createTempDirectory("jgit_test_");
+		MockSystemReader mockSystemReader = new MockSystemReader();
+		SystemReader.setInstance(mockSystemReader);
+
+		// Measure timer resolution before the test to avoid time critical tests
+		// are affected by time needed for measurement.
+		// The MockSystemReader must be configured first since we need to use
+		// the same one here
+		FS.getFileStoreAttributes(tmp.getParent());
+		systemConfig = new FileBasedConfig(
+				new File(tmp.toFile(), "systemgitconfig"), FS.DETECTED);
+		userConfig = new FileBasedConfig(systemConfig,
+				new File(tmp.toFile(), "usergitconfig"), FS.DETECTED);
+		// We have to set autoDetach to false for tests, because tests expect to
+		// be able to clean up by recursively removing the repository, and
+		// background GC might be in the middle of writing or deleting files,
+		// which would disrupt this.
+		userConfig.setBoolean(ConfigConstants.CONFIG_GC_SECTION, null,
+				ConfigConstants.CONFIG_KEY_AUTODETACH, false);
+		userConfig.save();
+		mockSystemReader.setSystemGitConfig(systemConfig);
+		mockSystemReader.setUserGitConfig(userConfig);
 
 		originalSystemReaderInstance = SystemReader.getInstance();
-		SystemReader.setInstance(systemReader);
-
-		mockSystemConfig = mock(FileBasedConfig.class);
-		mockUserConfig = mock(FileBasedConfig.class);
-		when(systemReader.openSystemConfig(any(), any()))
-				.thenReturn(mockSystemConfig);
-		when(systemReader.openUserConfig(any(), any()))
-				.thenReturn(mockUserConfig);
-
-		when(mockSystemConfig.getString(ConfigConstants.CONFIG_CORE_SECTION,
-				null, ConfigConstants.CONFIG_KEY_SUPPORTSATOMICFILECREATION))
-						.thenReturn(null);
+		SystemReader.setInstance(mockSystemReader);
 	}
 
 	@After
-	public void tearDown() {
+	public void tearDown() throws IOException {
 		SystemReader.setInstance(originalSystemReaderInstance);
+		FileUtils.delete(tmp.toFile(), FileUtils.RECURSIVE | FileUtils.RETRY);
 	}
 
 	@Test
@@ -94,32 +109,31 @@ public class FS_POSIXTest {
 
 	@Test
 	public void supportsAtomicCreateNewFile_shouldReturnTrueIfFlagIsSetInUserConfig() {
-		setAtomicCreateCreationFlag(mockUserConfig, "true");
+		setAtomicCreateCreationFlag(userConfig, "true");
 		assertTrue(new FS_POSIX().supportsAtomicCreateNewFile());
 	}
 
 	@Test
 	public void supportsAtomicCreateNewFile_shouldReturnTrueIfFlagIsSetInSystemConfig() {
-		setAtomicCreateCreationFlag(mockSystemConfig, "true");
+		setAtomicCreateCreationFlag(systemConfig, "true");
 		assertTrue(new FS_POSIX().supportsAtomicCreateNewFile());
 	}
 
 	@Test
 	public void supportsAtomicCreateNewFile_shouldReturnFalseIfFlagUnsetInUserConfig() {
-		setAtomicCreateCreationFlag(mockUserConfig, "false");
+		setAtomicCreateCreationFlag(userConfig, "false");
 		assertFalse(new FS_POSIX().supportsAtomicCreateNewFile());
 	}
 
 	@Test
 	public void supportsAtomicCreateNewFile_shouldReturnFalseIfFlagUnsetInSystemConfig() {
-		setAtomicCreateCreationFlag(mockSystemConfig, "false");
+		setAtomicCreateCreationFlag(systemConfig, "false");
 		assertFalse(new FS_POSIX().supportsAtomicCreateNewFile());
 	}
 
 	private void setAtomicCreateCreationFlag(FileBasedConfig config,
 			String value) {
-		when(config.getString(ConfigConstants.CONFIG_CORE_SECTION, null,
-				ConfigConstants.CONFIG_KEY_SUPPORTSATOMICFILECREATION))
-						.thenReturn(value);
+		config.setString(ConfigConstants.CONFIG_CORE_SECTION, null,
+				ConfigConstants.CONFIG_KEY_SUPPORTSATOMICFILECREATION, value);
 	}
 }