apply: reject input that touches outside the working area

[git.git] / line-range.c

diff --git a/line-range.c b/line-range.c
index 3942475c2fc8e48c7f0a2d7808f77a4f71a1cde6..de4e32f9424fbc0770756c3f61751fc69bfeb17e 100644 (file)
--- a/line-range.c
+++ b/line-range.c
@@ -6,6 +6,18 @@
 
 /*
  * Parse one item in the -L option
+ *
+ * 'begin' is applicable only to relative range anchors. Absolute anchors
+ * ignore this value.
+ *
+ * When parsing "-L A,B", parse_loc() is called once for A and once for B.
+ *
+ * When parsing A, 'begin' must be a negative number, the absolute value of
+ * which is the line at which relative start-of-range anchors should be
+ * based. Beginning of file is represented by -1.
+ *
+ * When parsing B, 'begin' must be the positive line number immediately
+ * following the line computed for 'A'.
  */
 static const char *parse_loc(const char *spec, nth_line_fn_t nth_line,
                             void *data, long lines, long begin, long *ret)
@@ -21,11 +33,13 @@ static const char *parse_loc(const char *spec, nth_line_fn_t nth_line,
         * for 20 lines, or "-L <something>,-5" for 5 lines ending at
         * <something>.
         */
-       if (1 < begin && (spec[0] == '+' || spec[0] == '-')) {
+       if (1 <= begin && (spec[0] == '+' || spec[0] == '-')) {
                num = strtol(spec + 1, &term, 10);
                if (term != spec + 1) {
                        if (!ret)
                                return term;
+                       if (num == 0)
+                               die("-L invalid empty range");
                        if (spec[0] == '-')
                                num = 0 - num;
                        if (0 < num)
@@ -40,10 +54,23 @@ static const char *parse_loc(const char *spec, nth_line_fn_t nth_line,
        }
        num = strtol(spec, &term, 10);
        if (term != spec) {
-               if (ret)
+               if (ret) {
+                       if (num <= 0)
+                               die("-L invalid line number: %ld", num);
                        *ret = num;
+               }
                return term;
        }
+
+       if (begin < 0) {
+               if (spec[0] != '^')
+                       begin = -begin;
+               else {
+                       begin = 1;
+                       spec++;
+               }
+       }
+
        if (spec[0] != '/')
                return spec;
 
@@ -83,7 +110,8 @@ static const char *parse_loc(const char *spec, nth_line_fn_t nth_line,
        else {
                char errbuf[1024];
                regerror(reg_error, &regexp, errbuf, 1024);
-               die("-L parameter '%s': %s", spec + 1, errbuf);
+               die("-L parameter '%s' starting at line %ld: %s",
+                   spec + 1, begin + 1, errbuf);
        }
 }
 
@@ -136,7 +164,7 @@ static const char *find_funcname_matching_regexp(xdemitconf_t *xecfg, const char
 }
 
 static const char *parse_range_funcname(const char *arg, nth_line_fn_t nth_line_cb,
-                                       void *cb_data, long lines, long *begin, long *end,
+                                       void *cb_data, long lines, long anchor, long *begin, long *end,
                                        const char *path)
 {
        char *pattern;
@@ -148,6 +176,11 @@ static const char *parse_range_funcname(const char *arg, nth_line_fn_t nth_line_
        int reg_error;
        regex_t regexp;
 
+       if (*arg == '^') {
+               anchor = 1;
+               arg++;
+       }
+
        assert(*arg == ':');
        term = arg+1;
        while (*term && *term != ':') {
@@ -162,7 +195,8 @@ static const char *parse_range_funcname(const char *arg, nth_line_fn_t nth_line_
 
        pattern = xstrndup(arg+1, term-(arg+1));
 
-       start = nth_line_cb(cb_data, 0);
+       anchor--; /* input is in human terms */
+       start = nth_line_cb(cb_data, anchor);
 
        drv = userdiff_find_by_path(path);
        if (drv && drv->funcname.pattern) {
@@ -180,7 +214,8 @@ static const char *parse_range_funcname(const char *arg, nth_line_fn_t nth_line_
 
        p = find_funcname_matching_regexp(xecfg, (char*) start, &regexp);
        if (!p)
-               die("-L parameter '%s': no match", pattern);
+               die("-L parameter '%s' starting at line %ld: no match",
+                   pattern, anchor + 1);
        *begin = 0;
        while (p > nth_line_cb(cb_data, *begin))
                (*begin)++;
@@ -208,19 +243,24 @@ static const char *parse_range_funcname(const char *arg, nth_line_fn_t nth_line_
 }
 
 int parse_range_arg(const char *arg, nth_line_fn_t nth_line_cb,
-                   void *cb_data, long lines, long *begin, long *end,
-                   const char *path)
+                   void *cb_data, long lines, long anchor,
+                   long *begin, long *end, const char *path)
 {
        *begin = *end = 0;
 
-       if (*arg == ':') {
-               arg = parse_range_funcname(arg, nth_line_cb, cb_data, lines, begin, end, path);
+       if (anchor < 1)
+               anchor = 1;
+       if (anchor > lines)
+               anchor = lines + 1;
+
+       if (*arg == ':' || (*arg == '^' && *(arg + 1) == ':')) {
+               arg = parse_range_funcname(arg, nth_line_cb, cb_data, lines, anchor, begin, end, path);
                if (!arg || *arg)
                        return -1;
                return 0;
        }
 
-       arg = parse_loc(arg, nth_line_cb, cb_data, lines, 1, begin);
+       arg = parse_loc(arg, nth_line_cb, cb_data, lines, -anchor, begin);
 
        if (*arg == ',')
                arg = parse_loc(arg + 1, nth_line_cb, cb_data, lines, *begin + 1, end);
@@ -238,8 +278,8 @@ int parse_range_arg(const char *arg, nth_line_fn_t nth_line_cb,
 
 const char *skip_range_arg(const char *arg)
 {
-       if (*arg == ':')
-               return parse_range_funcname(arg, NULL, NULL, 0, NULL, NULL, NULL);
+       if (*arg == ':' || (*arg == '^' && *(arg + 1) == ':'))
+               return parse_range_funcname(arg, NULL, NULL, 0, 0, NULL, NULL, NULL);
 
        arg = parse_loc(arg, NULL, NULL, 0, -1, NULL);