Add support for String Terminator to be ESC \ (#855)

This fixes support to properly identify the end of
OSC control sequences which can be terminated
with a BEL or ESC \.

Fixes #831

(cherry picked from commit 229c55c)

Co-authored-by: Jonah Graham <[email protected]>

Author: github-actions[bot]

terminal/plugins/org.eclipse.tm.terminal.control/META-INF/MANIFEST.MF

@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %pluginName
 Bundle-SymbolicName: org.eclipse.tm.terminal.control; singleton:=true
-Bundle-Version: 5.5.300.qualifier
+Bundle-Version: 5.5.301.qualifier
 Bundle-Activator: org.eclipse.tm.internal.terminal.control.impl.TerminalPlugin
 Bundle-Vendor: %providerName
 Bundle-Localization: plugin

terminal/plugins/org.eclipse.tm.terminal.control/src/org/eclipse/tm/internal/terminal/emulator/VT100Emulator.java

@@ -97,6 +97,12 @@ public class VT100Emulator implements ControlListener {
 	 */
 	private static final int ANSISTATE_EXPECTING_CHARSET_DESIGNATION = 5;
 
+	/**
+	 * For cases where the OSC (OS Command) ends with a multi-byte ST (i.e. ESC \)
+	 * we use this extra state.
+	 */
+	private static final int ANSISTATE_EXPECTING_OS_COMMAND_END = 6;
+
 	/**
 	 * This field holds the current state of the Finite TerminalState Automaton (FSA)
 	 * that recognizes ANSI escape sequences.
@@ -428,16 +434,27 @@ private void processNewText() throws IOException {
 				break;
 
 			case ANSISTATE_EXPECTING_OS_COMMAND:
-				// A BEL (\u0007) character marks the end of the OSC sequence.
+				// A BEL (\u0007) or ESC \ ('\e\\') character marks the end of the OSC sequence.
 
 				if (character == '\u0007') {
 					ansiState = ANSISTATE_INITIAL;
 					processAnsiOsCommand();
+				} else if (character == '\u001b') {
+					ansiState = ANSISTATE_EXPECTING_OS_COMMAND_END;
 				} else {
 					ansiOsCommand.append(character);
 				}
 				break;
 
+			case ANSISTATE_EXPECTING_OS_COMMAND_END:
+				ansiState = ANSISTATE_INITIAL;
+				if (character == '\\') {
+					processAnsiOsCommand();
+				} else {
+					Logger.log("Unsupported escape sequence: escape '" + ansiOsCommand + " \\e" + character + "'"); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
+				}
+				break;
+
 			case ANSISTATE_EXPECTING_DEC_PRIVATE_COMMAND:
 				// Parameters can appear after the '[?' in an escape sequence, but they
 				// are optional.

terminal/plugins/org.eclipse.tm.terminal.test/src/org/eclipse/tm/internal/terminal/emulator/VT100EmulatorTest.java

@@ -37,10 +37,18 @@ public class VT100EmulatorTest {
 	private static final String CLEAR_ENTIRE_SCREEN = "\033[2J";
 	private static final String SCROLL_REVERSE = "\033M";
 
-	private static String TITLE(String title) {
+	private static String TITLE_ST_BEL(String title) {
 		return "\033]0;" + title + "\007";
 	}
 
+	private static String TITLE_ST_ESC_BACKSLASH(String title) {
+		return "\033]0;" + title + "\033\\";
+	}
+
+	private static String TITLE(String title) {
+		return TITLE_ST_BEL(title);
+	}
+
 	private static String SCROLL_REGION(int startRow, int endRow) {
 		return "\033[" + startRow + ";" + endRow + "r";
 	}
@@ -340,4 +348,31 @@ public void testScrollReverseScrollingRegion() {
 		assertAll(() -> assertCursorLocation(2, expected.get(2).length()), () -> assertTextEquals(expected));
 	}
 
+	@Test
+	public void testStringTerminator() {
+		run( //
+				TITLE_ST_BEL("TITLE1"), //
+				"HELLO1", //
+				TITLE_ST_ESC_BACKSLASH("TITLE2"), //
+				"HELLO2", //
+				TITLE_ST_BEL("TITLE3"), //
+				"HELLO3", //
+				TITLE_ST_ESC_BACKSLASH("TITLE4") //
+		);
+		assertAll(() -> assertTextEquals("HELLO1HELLO2HELLO3"),
+				() -> assertEquals(List.of("TITLE1", "TITLE2", "TITLE3", "TITLE4"), control.getAllTitles()));
+	}
+
+	@Test
+	public void testMalformedStringTerminator() {
+		run( //
+				TITLE_ST_ESC_BACKSLASH("TITLE1"), //
+				"\033]0;" + "TITLE1" + "\033X", //
+				TITLE_ST_ESC_BACKSLASH("TITLE2"), //
+				"HELLO" //
+		);
+		assertAll(() -> assertTextEquals("HELLO"),
+				() -> assertEquals(List.of("TITLE1", "TITLE2"), control.getAllTitles()));
+	}
+
 }