Lint line continuation and whitespace issues

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 145 insertions, 2 deletions

diff --git a/mklint.c b/mklint.c
index 7302245..c21db40 100644
--- a/mklint.c
+++ b/mklint.c
@@ -7,10 +7,127 @@ NUSAGE(EXIT_ERROR, "[-f makefile]");
 int exit_status = 0;
 
 struct style style = {
-	.max_line_length = 120
+	.max_line_length = 120,
+	.only_empty_blank_lines = 1
 };
 
 
+static void
+set_line_continuation_joiner(struct line *line)
+{
+	if (line->len && line->data[line->len - 1] == '\\') {
+		line->data[--line->len] = '\0';
+		/* Doesn't matter here if the first non-white space is # */
+		line->continuation_joiner = line->data[0] == '\t' ? '\t' : ' ';
+	} else {
+		line->continuation_joiner = '\0';
+	}
+}
+
+
+static void
+check_line_continuations(struct line *lines, size_t nlines)
+{
+	size_t i, cont_from = 0;
+
+	for (i = 0; i < nlines; i++) {
+		set_line_continuation_joiner(&lines[i]);
+
+		if (lines[i].continuation_joiner &&
+		    (!i || !lines[i - 1].continuation_joiner) &&
+		    is_line_blank(&lines[i])) {
+			warnf_confusing(WC_CONTINUATION_OF_BLANK,
+			                "%s:%zu: initial line continuation on otherwise blank line, can cause confusion",
+			                lines[i].path, lines[i].lineno);
+		}
+
+		if (!lines[i].continuation_joiner &&
+		    i && lines[i - 1].continuation_joiner) {
+			warnf_confusing(WC_CONTINUATION_TO_BLANK,
+			                "%s:%zu: terminal line continuation to blank line, can cause confusion",
+			                lines[i].path, lines[i].lineno);
+		}
+
+		if (!lines[i].continuation_joiner && lines[i].eof) {
+			warnf_unspecified(WC_EOF_LINE_CONTINUATION,
+			                  "%s:%zu: line continuation at end of file, causes unspecified behaviour%s",
+			                  lines[i].path, lines[i].lineno,
+			                  (!lines[i].nest_level ? "" :
+			                   ", it is especially problematic in an included line"));
+			printinfof(WC_EOF_LINE_CONTINUATION, "this implementation will remove the line continuation");
+			lines[i].continuation_joiner = 0;
+		}
+
+		if (i && lines[i - 1].continuation_joiner && lines[i].len) {
+			if (!isspace(lines[i].data[0])) {
+				if (lines[cont_from].len && !isspace(lines[cont_from].data[lines[cont_from].len - 1])) {
+					warnf_confusing(WC_SPACELESS_CONTINUATION,
+					                "%s:%zu,%zu: <backslash> is proceeded by a non-white space "
+					                "character at the same time as the next line%s begins with "
+					                "a non-white space character, this can cause confusion as "
+					                "the make utility will add a whitespace",
+					                lines[cont_from].path, lines[cont_from].lineno,
+					                lines[i].lineno, i == cont_from + 1 ? "" :
+					                ", that consist of not only a <backslash>,");
+				}
+				warnf_confusing(WC_UNINDENTED_CONTINUATION,
+				                "%s:%zu: continuation of line is not indented, can cause confusion",
+				                lines[i].path, lines[i].lineno);
+			}
+			cont_from = i;
+		} else if (lines[i].continuation_joiner) {
+			cont_from = i;
+		}
+	}
+}
+
+
+
+static enum line_class
+classify_line(struct line *line)
+{
+	int warned_bad_space = 0;
+	char *s;
+
+	if (!line->len)
+		return EMPTY;
+
+	s = line->data;
+
+	while (isspace(*s)) {
+		if (!warned_bad_space && !isblank(*s)) {
+			warned_bad_space = 1;
+			warnf_undefined(WC_LEADING_BAD_SPACE,
+			                "%s:%zu: line contains leading white space other than"
+			                "<space> and <tab>, which causes undefined behaviour",
+			                line->path, line->lineno);
+			/* TODO what do we do here? */
+		}
+		s++;
+	}
+
+	if (*s == '#') {
+		if (line->data[0] != '#') {
+			/* TODO should not apply if command line */
+			warnf_undefined(WC_ILLEGAL_INDENT,
+			                "%s:%zu: comment has leading white space, which is not legal",
+			                line->path, line->lineno);
+			printinfof(WC_ILLEGAL_INDENT, "this implementation will recognise it as a comment line");
+		}
+		return COMMENT;
+
+	} else if (!*s) {
+		return BLANK;
+
+	} else if (line->data[0] == '\t') {
+		return COMMAND_LINE;
+
+	} else {
+		return OTHER;
+	}
+}
+
+
 int
 main(int argc, char *argv[])
 {
@@ -21,7 +138,7 @@ main(int argc, char *argv[])
 
 	libsimple_default_failure_exit = EXIT_ERROR;
 
-	/* make(1) shall support mixing of options and operands (uptil --) */
+	/* make(1) shall support mixing of options and operands (up to --) */
 	ARGBEGIN {
 	case 'f':
 		cmdline_opt_f(ARG(), &path);
@@ -43,6 +160,32 @@ main(int argc, char *argv[])
 		check_column_count(&lines[i]);
 	}
 
+	check_line_continuations(lines, nlines);
+
+	for (i = 0; i < nlines; i++) {
+		switch (classify_line(&lines[i])) {
+		case EMPTY:
+			break;
+
+		case BLANK:
+			if (style.only_empty_blank_lines) {
+				warnf_style(WC_NONEMPTY_BLANK, "%s:%zu: line is blank but not empty",
+				            lines[i].path, lines[i].lineno);
+			}
+			break;
+
+		case COMMENT:
+			break;
+
+		case COMMAND_LINE:
+		case OTHER:
+			break;
+
+		default:
+			abort();
+		}
+	}
+
 	free(lines);
 	return exit_status;
 }