Merge "Support built-in diff drivers for hunk header function names" into stable-6.10

4 files changed, 275 insertions, 13 deletions

diff --git a/org.eclipse.jgit/.settings/.api_filters b/org.eclipse.jgit/.settings/.api_filters
index 2c22f0231c..d3ae4cf376 100644
--- a/org.eclipse.jgit/.settings/.api_filters
+++ b/org.eclipse.jgit/.settings/.api_filters
@@ -1,5 +1,33 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <component id="org.eclipse.jgit" version="2">
+    <resource path="src/org/eclipse/jgit/diff/DiffDriver.java" type="org.eclipse.jgit.diff.DiffDriver">
+        <filter id="1109393411">
+            <message_arguments>
+                <message_argument value="6.10.1"/>
+                <message_argument value="org.eclipse.jgit.diff.DiffDriver"/>
+            </message_arguments>
+        </filter>
+    </resource>
+    <resource path="src/org/eclipse/jgit/diff/DiffFormatter.java" type="org.eclipse.jgit.diff.DiffFormatter">
+        <filter id="1142947843">
+            <message_arguments>
+                <message_argument value="6.10.1"/>
+                <message_argument value="format(EditList, RawText, RawText, DiffDriver)"/>
+            </message_arguments>
+        </filter>
+        <filter id="1142947843">
+            <message_arguments>
+                <message_argument value="6.10.1"/>
+                <message_argument value="format(FileHeader, RawText, RawText, DiffDriver)"/>
+            </message_arguments>
+        </filter>
+        <filter id="1142947843">
+            <message_arguments>
+                <message_argument value="6.10.1"/>
+                <message_argument value="writeHunkHeader(int, int, int, int, String)"/>
+            </message_arguments>
+        </filter>
+    </resource>
     <resource path="src/org/eclipse/jgit/gitrepo/RepoProject.java" type="org.eclipse.jgit.gitrepo.RepoProject">
         <filter id="1141899266">
             <message_arguments>
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/diff/DiffDriver.java b/org.eclipse.jgit/src/org/eclipse/jgit/diff/DiffDriver.java
new file mode 100644
index 0000000000..9ae1aaa298
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/diff/DiffDriver.java
@@ -0,0 +1,116 @@
+/*
+ * Copyright (c) 2024 Qualcomm Innovation Center, Inc.
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Distribution License v. 1.0 which is available at
+ * https://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+package org.eclipse.jgit.diff;
+
+import java.util.List;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+
+/**
+ * Built-in drivers for various languages, sorted by name. These drivers will be
+ * used to determine function names for a hunk.
+ * <p>
+ * When writing or updating patterns, assume the contents are syntactically
+ * correct. Patterns can be simple and need not cover all syntactical corner
+ * cases, as long as they are sufficiently permissive.
+ *
+ * @since 6.10.1
+ */
+@SuppressWarnings({"ImmutableEnumChecker", "nls"})
+public enum DiffDriver {
+	/**
+	 * Built-in diff driver for <a
+	 * href="https://learn.microsoft.com/en-us/cpp/cpp/cpp-language-reference">c++</a>
+	 */
+	cpp(List.of(
+			/* Jump targets or access declarations */
+			"^[ \\t]*[A-Za-z_][A-Za-z_0-9]*:\\s*($|/[/*])"), List.of(
+			/* functions/methods, variables, and compounds at top level */
+			"^((::\\s*)?[A-Za-z_].*)$")),
+	/**
+	 * Built-in diff driver for <a
+	 * href="https://devicetree-specification.readthedocs.io/en/stable/source-language.html">device
+	 * tree files</a>
+	 */
+	dts(List.of(";", "="), List.of(
+			/* lines beginning with a word optionally preceded by '&' or the root */
+			"^[ \\t]*((/[ \\t]*\\{|&?[a-zA-Z_]).*)")),
+	/**
+	 * Built-in diff driver for <a
+	 * href="https://docs.oracle.com/javase/specs/jls/se21/html/index.html">java</a>
+	 */
+	java(List.of(
+			"^[ \\t]*(catch|do|for|if|instanceof|new|return|switch|throw|while)"),
+			List.of(
+					/* Class, enum, interface, and record declarations */
+					"^[ \\t]*(([a-z-]+[ \\t]+)*(class|enum|interface|record)[ \\t]+.*)$",
+					/* Method definitions; note that constructor signatures are not */
+					/* matched because they are indistinguishable from method calls. */
+					"^[ \\t]*(([A-Za-z_<>&\\]\\[][?&<>.,A-Za-z_0-9]*[ \\t]+)+[A-Za-z_]"
+							+ "[A-Za-z_0-9]*[ \\t]*\\([^;]*)$")),
+	/**
+	 * Built-in diff driver for <a
+	 * href="https://docs.python.org/3/reference/index.html">python</a>
+	 */
+	python(List.of("^[ \\t]*((class|(async[ \\t]+)?def)[ \\t].*)$")),
+	/**
+	 * Built-in diff driver for <a *
+	 * href="https://doc.rust-lang.org/reference/introduction.html">java</a>
+	 */
+	rust(List.of("^[\\t ]*((pub(\\([^\\)]+\\))?[\\t ]+)?"
+			+ "((async|const|unsafe|extern([\\t ]+\"[^\"]+\"))[\\t ]+)?"
+			+ "(struct|enum|union|mod|trait|fn|impl|macro_rules!)[< \\t]+[^;]*)$"));
+
+	private final List<Pattern> negatePatterns;
+
+	private final List<Pattern> matchPatterns;
+
+	DiffDriver(List<String> negate, List<String> match, int flags) {
+		if (negate != null) {
+			this.negatePatterns = negate.stream()
+					.map(r -> Pattern.compile(r, flags))
+					.collect(Collectors.toList());
+		} else {
+			this.negatePatterns = null;
+		}
+		this.matchPatterns = match.stream().map(r -> Pattern.compile(r, flags))
+				.collect(Collectors.toList());
+	}
+
+	DiffDriver(List<String> match) {
+		this(null, match, 0);
+	}
+
+	DiffDriver(List<String> negate, List<String> match) {
+		this(negate, match, 0);
+	}
+
+	/**
+	 * Returns the list of patterns used to exclude certain lines from being
+	 * considered as function names.
+	 *
+	 * @return the list of negate patterns
+	 */
+	public List<Pattern> getNegatePatterns() {
+		return negatePatterns;
+	}
+
+	/**
+	 * Returns the list of patterns used to match lines for potential function
+	 * names.
+	 *
+	 * @return the list of match patterns
+	 */
+	public List<Pattern> getMatchPatterns() {
+		return matchPatterns;
+	}
+}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/diff/DiffFormatter.java b/org.eclipse.jgit/src/org/eclipse/jgit/diff/DiffFormatter.java
index 2f472b5c0a..fa446e18cd 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/diff/DiffFormatter.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/diff/DiffFormatter.java
@@ -30,7 +30,9 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 
+import java.util.regex.Pattern;
 import org.eclipse.jgit.api.errors.CanceledException;
+import org.eclipse.jgit.attributes.Attribute;
 import org.eclipse.jgit.diff.DiffAlgorithm.SupportedAlgorithm;
 import org.eclipse.jgit.diff.DiffEntry.ChangeType;
 import org.eclipse.jgit.dircache.DirCacheIterator;
@@ -703,7 +705,7 @@ public class DiffFormatter implements AutoCloseable {
 	 */
 	public void format(DiffEntry ent) throws IOException {
 		FormatResult res = createFormatResult(ent);
-		format(res.header, res.a, res.b);
+		format(res.header, res.a, res.b, getDiffDriver(ent));
 	}
 
 	private static byte[] writeGitLinkText(AbbreviatedObjectId id) {
@@ -749,11 +751,14 @@ public class DiffFormatter implements AutoCloseable {
 	 *            text source for the post-image version of the content. This
 	 *            must match the content of
 	 *            {@link org.eclipse.jgit.patch.FileHeader#getNewId()}.
+	 * @param diffDriver
+	 *            the diff driver used to obtain function names in hunk headers
 	 * @throws java.io.IOException
-	 *             writing to the supplied stream failed.
+	 *            writing to the supplied stream failed.
+	 * @since 6.10.1
 	 */
-	public void format(FileHeader head, RawText a, RawText b)
-			throws IOException {
+	public void format(FileHeader head, RawText a, RawText b,
+			DiffDriver diffDriver) throws IOException {
 		// Reuse the existing FileHeader as-is by blindly copying its
 		// header lines, but avoiding its hunks. Instead we recreate
 		// the hunks from the text instances we have been supplied.
@@ -763,8 +768,49 @@ public class DiffFormatter implements AutoCloseable {
 		if (!head.getHunks().isEmpty())
 			end = head.getHunks().get(0).getStartOffset();
 		out.write(head.getBuffer(), start, end - start);
-		if (head.getPatchType() == PatchType.UNIFIED)
-			format(head.toEditList(), a, b);
+		if (head.getPatchType() == PatchType.UNIFIED) {
+			format(head.toEditList(), a, b, diffDriver);
+		}
+	}
+
+	/**
+	 * Format a patch script, reusing a previously parsed FileHeader.
+	 * <p>
+	 * This formatter is primarily useful for editing an existing patch script
+	 * to increase or reduce the number of lines of context within the script.
+	 * All header lines are reused as-is from the supplied FileHeader.
+	 *
+	 * @param head
+	 * 		existing file header containing the header lines to copy.
+	 * @param a
+	 * 		text source for the pre-image version of the content. This must match
+	 * 		the content of {@link org.eclipse.jgit.patch.FileHeader#getOldId()}.
+	 * @param b
+	 * 		text source for the post-image version of the content. This must match
+	 * 		the content of {@link org.eclipse.jgit.patch.FileHeader#getNewId()}.
+	 * @throws java.io.IOException
+	 * 		writing to the supplied stream failed.
+	 */
+	public void format(FileHeader head, RawText a, RawText b)
+			throws IOException {
+		format(head, a, b, null);
+	}
+
+	/**
+	 * Formats a list of edits in unified diff format
+	 *
+	 * @param edits
+	 * 		some differences which have been calculated between A and B
+	 * @param a
+	 * 		the text A which was compared
+	 * @param b
+	 * 		the text B which was compared
+	 * @throws java.io.IOException
+	 * 		if an IO error occurred
+	 */
+	public void format(EditList edits, RawText a, RawText b)
+			throws IOException {
+		format(edits, a, b, null);
 	}
 
 	/**
@@ -776,11 +822,14 @@ public class DiffFormatter implements AutoCloseable {
 	 *            the text A which was compared
 	 * @param b
 	 *            the text B which was compared
+	 * @param diffDriver
+	 *            the diff driver used to obtain function names in hunk headers
 	 * @throws java.io.IOException
 	 *             if an IO error occurred
+	 * @since 6.10.1
 	 */
-	public void format(EditList edits, RawText a, RawText b)
-			throws IOException {
+	public void format(EditList edits, RawText a, RawText b,
+			DiffDriver diffDriver) throws IOException {
 		for (int curIdx = 0; curIdx < edits.size();) {
 			Edit curEdit = edits.get(curIdx);
 			final int endIdx = findCombinedEnd(edits, curIdx);
@@ -791,7 +840,8 @@ public class DiffFormatter implements AutoCloseable {
 			final int aEnd = (int) Math.min(a.size(), (long) endEdit.getEndA() + context);
 			final int bEnd = (int) Math.min(b.size(), (long) endEdit.getEndB() + context);
 
-			writeHunkHeader(aCur, aEnd, bCur, bEnd);
+			writeHunkHeader(aCur, aEnd, bCur, bEnd,
+					getFuncName(a, aCur - 1, diffDriver));
 
 			while (aCur < aEnd || bCur < bEnd) {
 				if (aCur < curEdit.getBeginA() || endIdx + 1 < curIdx) {
@@ -881,8 +931,30 @@ public class DiffFormatter implements AutoCloseable {
 	 * @throws java.io.IOException
 	 *             if an IO error occurred
 	 */
-	protected void writeHunkHeader(int aStartLine, int aEndLine,
-			int bStartLine, int bEndLine) throws IOException {
+	protected void writeHunkHeader(int aStartLine, int aEndLine, int bStartLine,
+			int bEndLine) throws IOException {
+		writeHunkHeader(aStartLine, aEndLine, bStartLine, bEndLine, null);
+	}
+
+	/**
+	 * Output a hunk header
+	 *
+	 * @param aStartLine
+	 *            within first source
+	 * @param aEndLine
+	 *            within first source
+	 * @param bStartLine
+	 *            within second source
+	 * @param bEndLine
+	 *            within second source
+	 * @param funcName
+	 *            function name of this hunk
+	 * @throws java.io.IOException
+	 *             if an IO error occurred
+	 * @since 6.10.1
+	 */
+	protected void writeHunkHeader(int aStartLine, int aEndLine, int bStartLine,
+			int bEndLine, String funcName) throws IOException {
 		out.write('@');
 		out.write('@');
 		writeRange('-', aStartLine + 1, aEndLine - aStartLine);
@@ -890,6 +962,10 @@ public class DiffFormatter implements AutoCloseable {
 		out.write(' ');
 		out.write('@');
 		out.write('@');
+		if (funcName != null) {
+			out.write(' ');
+			out.write(funcName.getBytes());
+		}
 		out.write('\n');
 	}
 
@@ -1247,4 +1323,46 @@ public class DiffFormatter implements AutoCloseable {
 	private static boolean end(Edit edit, int a, int b) {
 		return edit.getEndA() <= a && edit.getEndB() <= b;
 	}
+
+	private String getFuncName(RawText text, int startAt,
+			DiffDriver diffDriver) {
+		if (diffDriver != null) {
+			while (startAt > 0) {
+				String line = text.getString(startAt);
+				startAt--;
+				if (matchesAny(diffDriver.getNegatePatterns(), line)) {
+					continue;
+				}
+				if (matchesAny(diffDriver.getMatchPatterns(), line)) {
+					String funcName = line.replaceAll("^[ \\t]+", "");
+					return funcName.substring(0,
+							Math.min(funcName.length(), 80)).trim();
+				}
+			}
+		}
+		return null;
+	}
+
+	private boolean matchesAny(List<Pattern> patterns, String text) {
+		if (patterns != null) {
+			for (Pattern p : patterns) {
+				if (p.matcher(text).find()) {
+					return true;
+				}
+			}
+		}
+		return false;
+	}
+
+	private DiffDriver getDiffDriver(DiffEntry entry) {
+		Attribute diffAttr = entry.getDiffAttribute();
+		if (diffAttr != null) {
+			try {
+				return DiffDriver.valueOf(diffAttr.getValue());
+			} catch (IllegalArgumentException e) {
+				return null;
+			}
+		}
+		return null;
+	}
 }
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/diff/PatchIdDiffFormatter.java b/org.eclipse.jgit/src/org/eclipse/jgit/diff/PatchIdDiffFormatter.java
index 4343642f9a..b401bbe73d 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/diff/PatchIdDiffFormatter.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/diff/PatchIdDiffFormatter.java
@@ -44,8 +44,8 @@ public class PatchIdDiffFormatter extends DiffFormatter {
 	}
 
 	@Override
-	protected void writeHunkHeader(int aStartLine, int aEndLine,
-			int bStartLine, int bEndLine) throws IOException {
+	protected void writeHunkHeader(int aStartLine, int aEndLine, int bStartLine,
+			int bEndLine, String funcName) throws IOException {
 		// The hunk header is not taken into account for patch id calculation
 	}