UploadPack: Receive and parse client session-id

Before this change JGit did not support the session-id capability
implemented by native Git in UploadPack. This change implements
advertising the capability from the server and parsing the session-id
received from the client during an UploadPack operation.

Enable the transfer.advertisesid config setting to advertise the
capability from the server. The client may send a session-id capability
in response. If received, the value from this is parsed and available
via the getClientSID method on the UploadPack object.

This change does not add the capability to send a session-id from the
JGit client.

https://git-scm.com/docs/gitprotocol-capabilities#_session_idsession_id

Change-Id: Ib1b6929ff1b3a4528e767925b5e5c44b5d18182f
Signed-off-by: Josh Brown <sjoshbrown@google.com>

10 files changed, 206 insertions, 12 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/ProtocolV0ParserTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/ProtocolV0ParserTest.java
index b2a4af30ab..61b7fb619a 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/ProtocolV0ParserTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/ProtocolV0ParserTest.java
@@ -98,6 +98,25 @@ public class ProtocolV0ParserTest {
 						"f900c8326a43303685c46b279b9f70411bff1a4b"));
 	}
 
+	@Test
+	public void testRecvWantsWithSessionID()
+			throws PackProtocolException, IOException {
+		PacketLineIn pckIn = formatAsPacketLine(String.join(" ", "want",
+				"4624442d68ee402a94364191085b77137618633e", "thin-pack",
+				"agent=JGit.test/0.0.1", "session-id=client-session-id", "\n"),
+				"want f900c8326a43303685c46b279b9f70411bff1a4b\n",
+				PacketLineIn.end());
+		ProtocolV0Parser parser = new ProtocolV0Parser(defaultConfig());
+		FetchV0Request request = parser.recvWants(pckIn);
+		assertTrue(request.getClientCapabilities()
+				.contains(GitProtocolConstants.OPTION_THIN_PACK));
+		assertEquals(1, request.getClientCapabilities().size());
+		assertEquals("client-session-id", request.getClientSID());
+		assertThat(request.getWantIds(),
+				hasOnlyObjectIds("4624442d68ee402a94364191085b77137618633e",
+						"f900c8326a43303685c46b279b9f70411bff1a4b"));
+	}
+
 	/*
 	 * First round of protocol v0 negotiation. Client send wants, no
 	 * capabilities.
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/ProtocolV2ParserTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/ProtocolV2ParserTest.java
index 167b5b72c6..bab4a36cc4 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/ProtocolV2ParserTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/ProtocolV2ParserTest.java
@@ -361,4 +361,28 @@ public class ProtocolV2ParserTest {
 		assertEquals(2, req.getRefPrefixes().size());
 		assertThat(req.getRefPrefixes(), hasItems("refs/for", "refs/heads"));
 	}
+
+	@Test
+	public void testFetchWithSessionID() throws IOException {
+		PacketLineIn pckIn = formatAsPacketLine("session-id=the.client.sid",
+				PacketLineIn.end());
+
+		ProtocolV2Parser parser = new ProtocolV2Parser(
+				ConfigBuilder.start().allowFilter().done());
+		FetchV2Request request = parser.parseFetchRequest(pckIn);
+
+		assertEquals("the.client.sid", request.getClientSID());
+	}
+
+	@Test
+	public void testLsRefsWithSessionID() throws IOException {
+		PacketLineIn pckIn = formatAsPacketLine("session-id=the.client.sid",
+				PacketLineIn.delimiter(), PacketLineIn.end());
+
+		ProtocolV2Parser parser = new ProtocolV2Parser(
+				ConfigBuilder.getDefault());
+		LsRefsV2Request req = parser.parseLsRefsRequest(pckIn);
+
+		assertEquals("the.client.sid", req.getClientSID());
+	}
 }
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/UploadPackTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/UploadPackTest.java
index 7131905850..df48afef35 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/UploadPackTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/UploadPackTest.java
@@ -2429,6 +2429,24 @@ public class UploadPackTest {
 	}
 
 	@Test
+	public void testGetSessionIDValueProtocolV0() throws Exception {
+		RevCommit one = remote.commit().message("1").create();
+		remote.update("one", one);
+
+		UploadPack up = new UploadPack(server);
+		ByteArrayInputStream send = linesAsInputStream(
+				"want " + one.getName() + " agent=JGit-test/1.2.3"
+						+ " session-id=client-session-id\n",
+				PacketLineIn.end(),
+				"have 11cedf1b796d44207da702f7d420684022fc0f09\n", "done\n");
+
+		ByteArrayOutputStream recv = new ByteArrayOutputStream();
+		up.upload(send, recv, null);
+
+		assertEquals(up.getClientSID(), "client-session-id");
+	}
+
+	@Test
 	public void testGetPeerAgentProtocolV2() throws Exception {
 		server.getConfig().setString(ConfigConstants.CONFIG_PROTOCOL_SECTION,
 				null, ConfigConstants.CONFIG_KEY_VERSION,
@@ -2452,6 +2470,30 @@ public class UploadPackTest {
 		assertEquals(up.getPeerUserAgent(), "JGit-test/1.2.4");
 	}
 
+	@Test
+	public void testGetSessionIDValueProtocolV2() throws Exception {
+		server.getConfig().setString(ConfigConstants.CONFIG_PROTOCOL_SECTION,
+				null, ConfigConstants.CONFIG_KEY_VERSION,
+				TransferConfig.ProtocolVersion.V2.version());
+
+		RevCommit one = remote.commit().message("1").create();
+		remote.update("one", one);
+
+		UploadPack up = new UploadPack(server);
+		up.setExtraParameters(Sets.of("version=2"));
+
+		ByteArrayInputStream send = linesAsInputStream("command=fetch\n",
+				"agent=JGit-test/1.2.4\n", "session-id=client-session-id\n",
+				PacketLineIn.delimiter(), "want " + one.getName() + "\n",
+				"have 11cedf1b796d44207da702f7d420684022fc0f09\n", "done\n",
+				PacketLineIn.end());
+
+		ByteArrayOutputStream recv = new ByteArrayOutputStream();
+		up.upload(send, recv, null);
+
+		assertEquals(up.getClientSID(), "client-session-id");
+	}
+
 	private static class RejectAllRefFilter implements RefFilter {
 		@Override
 		public Map<String, Ref> filter(Map<String, Ref> refs) {
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchRequest.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchRequest.java
index 0663c5141c..009a70b7b3 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchRequest.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchRequest.java
@@ -40,6 +40,9 @@ abstract class FetchRequest {
 	@Nullable
 	final String agent;
 
+	@Nullable
+	final String clientSID;
+
 	/**
 	 * Initialize the common fields of a fetch request.
 	 *
@@ -61,12 +64,15 @@ abstract class FetchRequest {
 	 *            specific time, instead of depth
 	 * @param agent
 	 *            agent as reported by the client in the request body
+	 * @param clientSID
+	 *            agent as reported by the client in the request body
 	 */
 	FetchRequest(@NonNull Set<ObjectId> wantIds, int depth,
 			@NonNull Set<ObjectId> clientShallowCommits,
 			@NonNull FilterSpec filterSpec,
 			@NonNull Set<String> clientCapabilities, int deepenSince,
-			@NonNull List<String> deepenNots, @Nullable String agent) {
+			@NonNull List<String> deepenNots, @Nullable String agent,
+			@Nullable String clientSID) {
 		this.wantIds = requireNonNull(wantIds);
 		this.depth = depth;
 		this.clientShallowCommits = requireNonNull(clientShallowCommits);
@@ -75,6 +81,7 @@ abstract class FetchRequest {
 		this.deepenSince = deepenSince;
 		this.deepenNots = requireNonNull(deepenNots);
 		this.agent = agent;
+		this.clientSID = clientSID;
 	}
 
 	/**
@@ -160,4 +167,13 @@ abstract class FetchRequest {
 	String getAgent() {
 		return agent;
 	}
+
+	/**
+	 * @return string identifying the client session ID (as sent in the request body by the
+	 *         client)
+	 */
+	@Nullable
+	String getClientSID() {
+		return clientSID;
+	}
 }
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchV0Request.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchV0Request.java
index 4decb79513..ca3639d03c 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchV0Request.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchV0Request.java
@@ -30,9 +30,11 @@ final class FetchV0Request extends FetchRequest {
 			@NonNull Set<ObjectId> clientShallowCommits,
 			@NonNull FilterSpec filterSpec,
 			@NonNull Set<String> clientCapabilities, int deepenSince,
-			@NonNull List<String> deepenNotRefs, @Nullable String agent) {
+			@NonNull List<String> deepenNotRefs, @Nullable String agent,
+			@Nullable String clientSID) {
 		super(wantIds, depth, clientShallowCommits, filterSpec,
-				clientCapabilities, deepenSince, deepenNotRefs, agent);
+				clientCapabilities, deepenSince, deepenNotRefs, agent,
+				clientSID);
 	}
 
 	static final class Builder {
@@ -53,6 +55,8 @@ final class FetchV0Request extends FetchRequest {
 
 		String agent;
 
+		String clientSID;
+
 		/**
 		 * @param objectId
 		 *            object id received in a "want" line
@@ -149,6 +153,16 @@ final class FetchV0Request extends FetchRequest {
 		}
 
 		/**
+		 * @param clientSID
+		 *            session-id line sent by the client in the request body
+		 * @return this builder
+		 */
+		Builder setClientSID(String clientSID) {
+			this.clientSID = clientSID;
+			return this;
+		}
+
+		/**
 		 * @param filter
 		 *            the filter set in a filter line
 		 * @return this builder
@@ -160,7 +174,8 @@ final class FetchV0Request extends FetchRequest {
 
 		FetchV0Request build() {
 			return new FetchV0Request(wantIds, depth, clientShallowCommits,
-					filterSpec, clientCaps, deepenSince, deepenNots, agent);
+					filterSpec, clientCaps, deepenSince, deepenNots, agent,
+					clientSID);
 		}
 
 	}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchV2Request.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchV2Request.java
index 401744f6dd..3d4f38131c 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchV2Request.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/FetchV2Request.java
@@ -55,10 +55,11 @@ public final class FetchV2Request extends FetchRequest {
 			boolean doneReceived, boolean waitForDone,
 			@NonNull Set<String> clientCapabilities,
 			@Nullable String agent, @NonNull List<String> serverOptions,
-			boolean sidebandAll, @NonNull List<String> packfileUriProtocols) {
+			boolean sidebandAll, @NonNull List<String> packfileUriProtocols,
+			@Nullable String clientSID) {
 		super(wantIds, depth, clientShallowCommits, filterSpec,
 				clientCapabilities, deepenSince,
-				deepenNots, agent);
+				deepenNots, agent, clientSID);
 		this.peerHas = requireNonNull(peerHas);
 		this.wantedRefs = requireNonNull(wantedRefs);
 		this.doneReceived = doneReceived;
@@ -157,6 +158,9 @@ public final class FetchV2Request extends FetchRequest {
 		@Nullable
 		String agent;
 
+		@Nullable
+		String clientSID;
+
 		final List<String> serverOptions = new ArrayList<>();
 
 		boolean sidebandAll;
@@ -317,6 +321,17 @@ public final class FetchV2Request extends FetchRequest {
 		}
 
 		/**
+		 * @param clientSIDValue
+		 *            the client-supplied session capability, without the
+		 *            leading "session-id="
+		 * @return this builder
+		 */
+		Builder setClientSID(@Nullable String clientSIDValue) {
+			clientSID = clientSIDValue;
+			return this;
+		}
+
+		/**
 		 * Records an application-specific option supplied in a server-option
 		 * line, for later retrieval with
 		 * {@link FetchV2Request#getServerOptions}.
@@ -354,7 +369,8 @@ public final class FetchV2Request extends FetchRequest {
 					depth, filterSpec, doneReceived, waitForDone, clientCapabilities,
 					agent, Collections.unmodifiableList(serverOptions),
 					sidebandAll,
-					Collections.unmodifiableList(packfileUriProtocols));
+					Collections.unmodifiableList(packfileUriProtocols),
+					clientSID);
 		}
 	}
 }
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/LsRefsV2Request.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/LsRefsV2Request.java
index f68d9c8135..856047ee19 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/LsRefsV2Request.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/LsRefsV2Request.java
@@ -36,17 +36,21 @@ public final class LsRefsV2Request {
 	@Nullable
 	private final String agent;
 
+	private final String clientSID;
+
 	@NonNull
 	private final List<String> serverOptions;
 
 	private LsRefsV2Request(List<String> refPrefixes, boolean symrefs,
 			boolean peel, @Nullable String agent,
-			@NonNull List<String> serverOptions) {
+			@NonNull List<String> serverOptions,
+			@Nullable String clientSID) {
 		this.refPrefixes = refPrefixes;
 		this.symrefs = symrefs;
 		this.peel = peel;
 		this.agent = agent;
 		this.serverOptions = requireNonNull(serverOptions);
+		this.clientSID = clientSID;
 	}
 
 	/** @return ref prefixes that the client requested. */
@@ -75,6 +79,16 @@ public final class LsRefsV2Request {
 	}
 
 	/**
+	 * @return session-id as reported by the client
+	 *
+	 * @since 6.4
+	 */
+	@Nullable
+	public String getClientSID() {
+		return clientSID;
+	}
+
+	/**
 	 * Get application-specific options provided by the client using
 	 * --server-option.
 	 * <p>
@@ -109,6 +123,8 @@ public final class LsRefsV2Request {
 
 		private String agent;
 
+		private String clientSID;
+
 		private Builder() {
 		}
 
@@ -171,11 +187,28 @@ public final class LsRefsV2Request {
 			return this;
 		}
 
+		/**
+		 * Value of a session-id line received after the command and before the
+		 * arguments. E.g. "session-id=a.b.c" should set "a.b.c".
+		 *
+		 * @param value
+		 *            the client-supplied session-id capability, without leading
+		 *            "session-id="
+		 * @return this builder
+		 *
+		 * @since 6.4
+		 */
+		public Builder setClientSID(@Nullable String value) {
+			clientSID = value;
+			return this;
+		}
+
 		/** @return LsRefsV2Request */
 		public LsRefsV2Request build() {
 			return new LsRefsV2Request(
 					Collections.unmodifiableList(refPrefixes), symrefs, peel,
-					agent, Collections.unmodifiableList(serverOptions));
+					agent, Collections.unmodifiableList(serverOptions),
+					clientSID);
 		}
 	}
 }
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/ProtocolV0Parser.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/ProtocolV0Parser.java
index 21a492577f..9d055519a5 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/ProtocolV0Parser.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/ProtocolV0Parser.java
@@ -152,6 +152,7 @@ final class ProtocolV0Parser {
 					FirstWant firstLine = FirstWant.fromLine(line);
 					reqBuilder.addClientCapabilities(firstLine.getCapabilities());
 					reqBuilder.setAgent(firstLine.getAgent());
+					reqBuilder.setClientSID(firstLine.getClientSID());
 					line = firstLine.getLine();
 				}
 			}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/ProtocolV2Parser.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/ProtocolV2Parser.java
index b38deb69c0..c4129ff4d0 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/ProtocolV2Parser.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/ProtocolV2Parser.java
@@ -20,6 +20,7 @@ import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_SIDEBAND_AL
 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_SIDE_BAND_64K;
 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_THIN_PACK;
 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_WAIT_FOR_DONE;
+import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_SESSION_ID;
 import static org.eclipse.jgit.transport.GitProtocolConstants.PACKET_DEEPEN;
 import static org.eclipse.jgit.transport.GitProtocolConstants.PACKET_DEEPEN_NOT;
 import static org.eclipse.jgit.transport.GitProtocolConstants.PACKET_DEEPEN_SINCE;
@@ -63,10 +64,12 @@ final class ProtocolV2Parser {
 	 */
 	private static String consumeCapabilities(PacketLineIn pckIn,
 			Consumer<String> serverOptionConsumer,
-			Consumer<String> agentConsumer) throws IOException {
+			Consumer<String> agentConsumer,
+			Consumer<String> clientSIDConsumer) throws IOException {
 
 		String serverOptionPrefix = OPTION_SERVER_OPTION + '=';
 		String agentPrefix = OPTION_AGENT + '=';
+		String clientSIDPrefix = OPTION_SESSION_ID + '=';
 
 		String line = pckIn.readString();
 		while (!PacketLineIn.isDelimiter(line) && !PacketLineIn.isEnd(line)) {
@@ -75,6 +78,9 @@ final class ProtocolV2Parser {
 						.accept(line.substring(serverOptionPrefix.length()));
 			} else if (line.startsWith(agentPrefix)) {
 				agentConsumer.accept(line.substring(agentPrefix.length()));
+			} else if (line.startsWith(clientSIDPrefix)) {
+				clientSIDConsumer
+						.accept(line.substring(clientSIDPrefix.length()));
 			} else {
 				// Unrecognized capability. Ignore it.
 			}
@@ -108,7 +114,8 @@ final class ProtocolV2Parser {
 
 		String line = consumeCapabilities(pckIn,
 				serverOption -> reqBuilder.addServerOption(serverOption),
-				agent -> reqBuilder.setAgent(agent));
+				agent -> reqBuilder.setAgent(agent),
+				clientSID -> reqBuilder.setClientSID(clientSID));
 
 		if (PacketLineIn.isEnd(line)) {
 			return reqBuilder.build();
@@ -235,7 +242,8 @@ final class ProtocolV2Parser {
 
 		String line = consumeCapabilities(pckIn,
 				serverOption -> builder.addServerOption(serverOption),
-				agent -> builder.setAgent(agent));
+				agent -> builder.setAgent(agent),
+				clientSID -> builder.setClientSID(clientSID));
 
 		if (PacketLineIn.isEnd(line)) {
 			return builder.build();
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/UploadPack.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/UploadPack.java
index 65dbf12b2f..a7ce1d7c21 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/UploadPack.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/UploadPack.java
@@ -34,6 +34,7 @@ import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_SHALLOW;
 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_SIDEBAND_ALL;
 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_SIDE_BAND;
 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_SIDE_BAND_64K;
+import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_SESSION_ID;
 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_THIN_PACK;
 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_WAIT_FOR_DONE;
 import static org.eclipse.jgit.transport.GitProtocolConstants.PACKET_ACK;
@@ -1382,6 +1383,10 @@ public class UploadPack implements Closeable {
 						: "")
 				+ OPTION_SHALLOW);
 		caps.add(CAPABILITY_SERVER_OPTION);
+		if (transferConfig.isAllowReceiveClientSID()) {
+			caps.add(OPTION_SESSION_ID);
+		}
+
 		return caps;
 	}
 
@@ -1700,6 +1705,21 @@ public class UploadPack implements Closeable {
 		return userAgent;
 	}
 
+	/**
+	 * Get the session ID if received from the client.
+	 *
+	 * @return The session ID if it has been received from the client.
+	 * @since 6.4
+	 */
+	@Nullable
+	public String getClientSID() {
+		if (currentRequest == null) {
+			return null;
+		}
+
+		return currentRequest.getClientSID();
+	}
+
 	private boolean negotiate(FetchRequest req,
 			PackStatistics.Accumulator accumulator,
 			PacketLineOut pckOut)