main: trim whitespace prefix from tag name

Close universal-ctags#1141

Original issue:

    [yamato@x201]~/var/ctags-github% cat /tmp/foo.html
    cat /tmp/foo.html
    <h1> ABC</h1>

    [yamato@x201]~/var/ctags-github% ./ctags /tmp/foo.html
    ./ctags /tmp/foo.html
    [yamato@x201]~/var/ctags-github% cat tags
    cat tags
     ABC    /tmp/foo.html   /^<h1> ABC<\/h1>$/;"    h
    !_TAG_FILE_FORMAT   2   /extended format; --format=1 will not append ;" to lines/
    !_TAG_FILE_SORTED   1   /0=unsorted, 1=sorted, 2=foldcase/
    !_TAG_PROGRAM_AUTHOR    Universal Ctags Team    //
    !_TAG_PROGRAM_NAME  Universal Ctags /Derived from Exuberant Ctags/
    !_TAG_PROGRAM_URL   https://ctags.io/   /official site/
    !_TAG_PROGRAM_VERSION   0.0.0   /25bad34/

    Look at the whiespace before ABC.

    If a tag name is started with a whitespace, it is printed in tags file before pseudo tags.
    I guess this behavior make client tools get into crazy.

This patch trims whitespace characters at the head of tag name.

trimPrefixedWhitespaces() function is much simpflied by @codebrainz.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>

Units/parser-html.r/whitespace-prefixed.html.d/expected.tags

@@ -0,0 +1 @@
+heading1	input.html	/^<\/h1>$/;"	h

Units/parser-html.r/whitespace-prefixed.html.d/input.html

@@ -0,0 +1,3 @@
+<h1>
+    heading1
+</h1>

Units/parser-javascript.r/js-broken-template.d/expected.tags

@@ -1 +0,0 @@
-\n	input.js	/^let`$/;"	v

main/entry.c

@@ -1280,8 +1280,25 @@ static void makeTagEntriesForSubwords (tagEntryInfo *const subtag)
 	stringListDelete (list);
 }
 
-extern int makeTagEntry (const tagEntryInfo *const tag)
+static char *trimPrefixedWhitespaces (const char *name)
 {
+	const char *start;
+
+	for (start = name; isspace(*start); start++)
+		;
+
+	if (start != name)
+		return eStrdup (start);
+
+	return NULL;
+}
+
+extern int makeTagEntry (const tagEntryInfo *const tag_const)
+{
+	char *trimmed_name;
+	const tagEntryInfo *tag = tag_const;
+	tagEntryInfo tag_backingstore;
+
 	int r = CORK_NIL;
 	Assert (tag->name != NULL);
 
@@ -1295,6 +1312,14 @@ extern int makeTagEntry (const tagEntryInfo *const tag)
 			return CORK_NIL;
 	}
 
+	trimmed_name = trimPrefixedWhitespaces (tag->name);
+	if (trimmed_name)
+	{
+		tag_backingstore = *tag_const;
+		tag = &tag_backingstore;
+		tag_backingstore.name = trimmed_name;
+	}
+
 	if (tag->name [0] == '\0' && (!tag->placeholder))
 	{
 		if (!doesInputLanguageAllowNullTag())
@@ -1314,6 +1339,8 @@ extern int makeTagEntry (const tagEntryInfo *const tag)
 		makeTagEntriesForSubwords (&subtag);
 	}
 out:
+	if (trimmed_name)
+		eFree (trimmed_name);
 	return r;
 }