Merge branch 'jc/ignore-cr-at-eol'

The "diff" family of commands learned to ignore differences in
carriage return at the end of line.

* jc/ignore-cr-at-eol:
  diff: --ignore-cr-at-eol
  xdiff: reassign xpparm_t.flags bits

2 files changed, 52 insertions, 12 deletions

diff --git a/xdiff/xdiff.h b/xdiff/xdiff.h
index 785ecb0899..915591f7d4 100644
--- a/xdiff/xdiff.h
+++ b/xdiff/xdiff.h
@@ -27,22 +27,28 @@
 extern "C" {
 #endif /* #ifdef __cplusplus */
 
+/* xpparm_t.flags */
+#define XDF_NEED_MINIMAL (1 << 0)
+
+#define XDF_IGNORE_WHITESPACE (1 << 1)
+#define XDF_IGNORE_WHITESPACE_CHANGE (1 << 2)
+#define XDF_IGNORE_WHITESPACE_AT_EOL (1 << 3)
+#define XDF_IGNORE_CR_AT_EOL (1 << 4)
+#define XDF_WHITESPACE_FLAGS (XDF_IGNORE_WHITESPACE | \
+			      XDF_IGNORE_WHITESPACE_CHANGE | \
+			      XDF_IGNORE_WHITESPACE_AT_EOL | \
+			      XDF_IGNORE_CR_AT_EOL)
 
-#define XDF_NEED_MINIMAL (1 << 1)
-#define XDF_IGNORE_WHITESPACE (1 << 2)
-#define XDF_IGNORE_WHITESPACE_CHANGE (1 << 3)
-#define XDF_IGNORE_WHITESPACE_AT_EOL (1 << 4)
-#define XDF_WHITESPACE_FLAGS (XDF_IGNORE_WHITESPACE | XDF_IGNORE_WHITESPACE_CHANGE | XDF_IGNORE_WHITESPACE_AT_EOL)
+#define XDF_IGNORE_BLANK_LINES (1 << 7)
 
-#define XDF_PATIENCE_DIFF (1 << 5)
-#define XDF_HISTOGRAM_DIFF (1 << 6)
+#define XDF_PATIENCE_DIFF (1 << 14)
+#define XDF_HISTOGRAM_DIFF (1 << 15)
 #define XDF_DIFF_ALGORITHM_MASK (XDF_PATIENCE_DIFF | XDF_HISTOGRAM_DIFF)
 #define XDF_DIFF_ALG(x) ((x) & XDF_DIFF_ALGORITHM_MASK)
 
-#define XDF_IGNORE_BLANK_LINES (1 << 7)
-
-#define XDF_INDENT_HEURISTIC (1 << 8)
+#define XDF_INDENT_HEURISTIC (1 << 23)
 
+/* xdemitconf_t.flags */
 #define XDL_EMIT_FUNCNAMES (1 << 0)
 #define XDL_EMIT_FUNCCONTEXT (1 << 2)
 
diff --git a/xdiff/xutils.c b/xdiff/xutils.c
index 088001db4f..88e5995535 100644
--- a/xdiff/xutils.c
+++ b/xdiff/xutils.c
@@ -156,6 +156,24 @@ int xdl_blankline(const char *line, long size, long flags)
 	return (i == size);
 }
 
+/*
+ * Have we eaten everything on the line, except for an optional
+ * CR at the very end?
+ */
+static int ends_with_optional_cr(const char *l, long s, long i)
+{
+	int complete = s && l[s-1] == '\n';
+
+	if (complete)
+		s--;
+	if (s == i)
+		return 1;
+	/* do not ignore CR at the end of an incomplete line */
+	if (complete && s == i + 1 && l[i] == '\r')
+		return 1;
+	return 0;
+}
+
 int xdl_recmatch(const char *l1, long s1, const char *l2, long s2, long flags)
 {
 	int i1, i2;
@@ -170,7 +188,8 @@ int xdl_recmatch(const char *l1, long s1, const char *l2, long s2, long flags)
 
 	/*
 	 * -w matches everything that matches with -b, and -b in turn
-	 * matches everything that matches with --ignore-space-at-eol.
+	 * matches everything that matches with --ignore-space-at-eol,
+	 * which in turn matches everything that matches with --ignore-cr-at-eol.
 	 *
 	 * Each flavor of ignoring needs different logic to skip whitespaces
 	 * while we have both sides to compare.
@@ -204,6 +223,14 @@ int xdl_recmatch(const char *l1, long s1, const char *l2, long s2, long flags)
 			i1++;
 			i2++;
 		}
+	} else if (flags & XDF_IGNORE_CR_AT_EOL) {
+		/* Find the first difference and see how the line ends */
+		while (i1 < s1 && i2 < s2 && l1[i1] == l2[i2]) {
+			i1++;
+			i2++;
+		}
+		return (ends_with_optional_cr(l1, s1, i1) &&
+			ends_with_optional_cr(l2, s2, i2));
 	}
 
 	/*
@@ -230,9 +257,16 @@ static unsigned long xdl_hash_record_with_whitespace(char const **data,
 		char const *top, long flags) {
 	unsigned long ha = 5381;
 	char const *ptr = *data;
+	int cr_at_eol_only = (flags & XDF_WHITESPACE_FLAGS) == XDF_IGNORE_CR_AT_EOL;
 
 	for (; ptr < top && *ptr != '\n'; ptr++) {
-		if (XDL_ISSPACE(*ptr)) {
+		if (cr_at_eol_only) {
+			/* do not ignore CR at the end of an incomplete line */
+			if (*ptr == '\r' &&
+			    (ptr + 1 < top && ptr[1] == '\n'))
+				continue;
+		}
+		else if (XDL_ISSPACE(*ptr)) {
 			const char *ptr2 = ptr;
 			int at_eol;
 			while (ptr + 1 < top && XDL_ISSPACE(ptr[1])