Teach "diff --check" about new blank lines at end

[thirdparty/git.git] / ws.c

diff --git a/ws.c b/ws.c
index d09b9df89a7e19367640d4c6ad64ff828d01d26f..7a7ff130a34942506e6068105ac5946c9404bf18 100644 (file)
--- a/ws.c
+++ b/ws.c
@@ -14,6 +14,7 @@ static struct whitespace_rule {
        { "trailing-space", WS_TRAILING_SPACE },
        { "space-before-tab", WS_SPACE_BEFORE_TAB },
        { "indent-with-non-tab", WS_INDENT_WITH_NON_TAB },
+       { "cr-at-eol", WS_CR_AT_EOL },
 };
 
 unsigned parse_whitespace_rule(const char *string)
@@ -116,14 +117,15 @@ char *whitespace_error_string(unsigned ws)
 }
 
 /* If stream is non-NULL, emits the line after checking. */
-unsigned check_and_emit_line(const char *line, int len, unsigned ws_rule,
-                            FILE *stream, const char *set,
-                            const char *reset, const char *ws)
+static unsigned ws_check_emit_1(const char *line, int len, unsigned ws_rule,
+                               FILE *stream, const char *set,
+                               const char *reset, const char *ws)
 {
        unsigned result = 0;
        int written = 0;
        int trailing_whitespace = -1;
        int trailing_newline = 0;
+       int trailing_carriage_return = 0;
        int i;
 
        /* Logic is simpler if we temporarily ignore the trailing newline. */
@@ -131,6 +133,11 @@ unsigned check_and_emit_line(const char *line, int len, unsigned ws_rule,
                trailing_newline = 1;
                len--;
        }
+       if ((ws_rule & WS_CR_AT_EOL) &&
+           len > 0 && line[len - 1] == '\r') {
+               trailing_carriage_return = 1;
+               len--;
+       }
 
        /* Check for trailing whitespace. */
        if (ws_rule & WS_TRAILING_SPACE) {
@@ -176,8 +183,10 @@ unsigned check_and_emit_line(const char *line, int len, unsigned ws_rule,
        }
 
        if (stream) {
-               /* Now the rest of the line starts at written.
-                * The non-highlighted part ends at trailing_whitespace. */
+               /*
+                * Now the rest of the line starts at "written".
+                * The non-highlighted part ends at "trailing_whitespace".
+                */
                if (trailing_whitespace == -1)
                        trailing_whitespace = len;
 
@@ -196,8 +205,141 @@ unsigned check_and_emit_line(const char *line, int len, unsigned ws_rule,
                            len - trailing_whitespace, 1, stream);
                        fputs(reset, stream);
                }
+               if (trailing_carriage_return)
+                       fputc('\r', stream);
                if (trailing_newline)
                        fputc('\n', stream);
        }
        return result;
 }
+
+void ws_check_emit(const char *line, int len, unsigned ws_rule,
+                  FILE *stream, const char *set,
+                  const char *reset, const char *ws)
+{
+       (void)ws_check_emit_1(line, len, ws_rule, stream, set, reset, ws);
+}
+
+unsigned ws_check(const char *line, int len, unsigned ws_rule)
+{
+       return ws_check_emit_1(line, len, ws_rule, NULL, NULL, NULL, NULL);
+}
+
+int ws_blank_line(const char *line, int len, unsigned ws_rule)
+{
+       /*
+        * We _might_ want to treat CR differently from other
+        * whitespace characters when ws_rule has WS_CR_AT_EOL, but
+        * for now we just use this stupid definition.
+        */
+       while (len-- > 0) {
+               if (!isspace(*line))
+                       return 0;
+               line++;
+       }
+       return 1;
+}
+
+/* Copy the line to the buffer while fixing whitespaces */
+int ws_fix_copy(char *dst, const char *src, int len, unsigned ws_rule, int *error_count)
+{
+       /*
+        * len is number of bytes to be copied from src, starting
+        * at src.  Typically src[len-1] is '\n', unless this is
+        * the incomplete last line.
+        */
+       int i;
+       int add_nl_to_tail = 0;
+       int add_cr_to_tail = 0;
+       int fixed = 0;
+       int last_tab_in_indent = -1;
+       int last_space_in_indent = -1;
+       int need_fix_leading_space = 0;
+       char *buf;
+
+       /*
+        * Strip trailing whitespace
+        */
+       if ((ws_rule & WS_TRAILING_SPACE) &&
+           (2 <= len && isspace(src[len-2]))) {
+               if (src[len - 1] == '\n') {
+                       add_nl_to_tail = 1;
+                       len--;
+                       if (1 < len && src[len - 1] == '\r') {
+                               add_cr_to_tail = !!(ws_rule & WS_CR_AT_EOL);
+                               len--;
+                       }
+               }
+               if (0 < len && isspace(src[len - 1])) {
+                       while (0 < len && isspace(src[len-1]))
+                               len--;
+                       fixed = 1;
+               }
+       }
+
+       /*
+        * Check leading whitespaces (indent)
+        */
+       for (i = 0; i < len; i++) {
+               char ch = src[i];
+               if (ch == '\t') {
+                       last_tab_in_indent = i;
+                       if ((ws_rule & WS_SPACE_BEFORE_TAB) &&
+                           0 <= last_space_in_indent)
+                           need_fix_leading_space = 1;
+               } else if (ch == ' ') {
+                       last_space_in_indent = i;
+                       if ((ws_rule & WS_INDENT_WITH_NON_TAB) &&
+                           8 <= i - last_tab_in_indent)
+                               need_fix_leading_space = 1;
+               } else
+                       break;
+       }
+
+       buf = dst;
+       if (need_fix_leading_space) {
+               /* Process indent ourselves */
+               int consecutive_spaces = 0;
+               int last = last_tab_in_indent + 1;
+
+               if (ws_rule & WS_INDENT_WITH_NON_TAB) {
+                       /* have "last" point at one past the indent */
+                       if (last_tab_in_indent < last_space_in_indent)
+                               last = last_space_in_indent + 1;
+                       else
+                               last = last_tab_in_indent + 1;
+               }
+
+               /*
+                * between src[0..last-1], strip the funny spaces,
+                * updating them to tab as needed.
+                */
+               for (i = 0; i < last; i++) {
+                       char ch = src[i];
+                       if (ch != ' ') {
+                               consecutive_spaces = 0;
+                               *dst++ = ch;
+                       } else {
+                               consecutive_spaces++;
+                               if (consecutive_spaces == 8) {
+                                       *dst++ = '\t';
+                                       consecutive_spaces = 0;
+                               }
+                       }
+               }
+               while (0 < consecutive_spaces--)
+                       *dst++ = ' ';
+               len -= last;
+               src += last;
+               fixed = 1;
+       }
+
+       memcpy(dst, src, len);
+       if (add_cr_to_tail)
+               dst[len++] = '\r';
+       if (add_nl_to_tail)
+               dst[len++] = '\n';
+       if (fixed && error_count)
+               (*error_count)++;
+       return dst + len - buf;
+}