readtags: experimental support for !_READTAGS_INCLUDE pseudo tag

  $ cat tags
  !_READTAGS_INCLUDE	podman.tags	//
  !_READTAGS_INCLUDE	glibc.tags	//
  !_READTAGS_INCLUDE	coreutils832.tags	//
  !_TAG_FILE_FORMAT	2	/extended format; --format=1 will not append ;" to lines/
  !_TAG_FILE_SORTED	1	/0=unsorted, 1=sorted, 2=foldcase/
  !_TAG_OUTPUT_EXCMD	mixed	/number, pattern, mixed, or combineV2/
  !_TAG_OUTPUT_FILESEP	slash	/slash or backslash/
  !_TAG_OUTPUT_MODE	u-ctags	/u-ctags or e-ctags/
  !_TAG_OUTPUT_VERSION	0.0	/current.age/
  !_TAG_PATTERN_LENGTH_LIMIT	96	/0 for no limit/
  !_TAG_PROC_CWD	/home/yamato/var/ctags-github/	//
  !_TAG_PROGRAM_AUTHOR	Universal Ctags Team	//
  !_TAG_PROGRAM_NAME	Cons Tags	/A tool for generating aggregate tags/
  !_TAG_PROGRAM_URL	https://ctags.io/	/official site/
  !_TAG_PROGRAM_VERSION	0.0.0	//
  $ ./readtags --list-included
  podman.tags
  glibc.tags
  coreutils832.tags
  $ ./readtags -A rootful
  rootful	/home/yamato/var/podman/pkg/machine/e2e/config_init_test.go	/^	rootful            bool$/
  rootful	/home/yamato/var/podman/pkg/machine/e2e/config_set_test.go	/^	rootful            bool$/

Signed-off-by: Masatake YAMATO <[email protected]>

Author: masatake

extra-cmds/readtags-cmd.c

@@ -46,6 +46,7 @@ typedef struct tagFileX {
 struct inputSpec {
 	const char *tagFileName;
 	char *tempFileName;
+	bool indirect;
 };
 
 struct actionSpec {
@@ -54,6 +55,7 @@ struct actionSpec {
 		ACTION_FIND = 1 << 0,
 		ACTION_LIST = 1 << 1,
 		ACTION_LIST_PTAGS = 1 << 2,
+		ACTION_LIST_INCLUDED = 1 << 3,
 	} action;
 	const char *name;			/* for ACTION_FIND */
 	bool canonicalizing;
@@ -605,6 +607,8 @@ static const char *const Usage =
 	"        \"-\" indicates arguments after this as NAME(s) even if they start with -.\n"
 	"    -D | --list-pseudo-tags\n"
 	"        List pseudo tags.\n"
+	"    -L | --list-included\n"
+	"        List included tag files.\n"
 	"Options:\n"
 	"    -d | --debug\n"
 	"        Turn on debugging output.\n"
@@ -711,24 +715,55 @@ static void printVersion(void)
 static void deleteInputSpec (void *data)
 {
 	struct inputSpec *inputSpec = data;
+
+	if (inputSpec->indirect)
+		eFree ((void *)inputSpec->tagFileName);
 	if (inputSpec->tempFileName)
 	{
 		remove (inputSpec->tempFileName);
 		eFree (inputSpec->tempFileName);
 	}
+
 	eFree (data);
 }
 
-static void addInputSpec (ptrArray *inputSpecs, const char *name)
+static void addInputSpec (ptrArray *inputSpecs, const char *name, bool indirect)
 {
 	struct inputSpec *i = eMalloc (sizeof (struct inputSpec));
 
-	i->tagFileName = name;
+	i->tagFileName = indirect? eStrdup (name): name;
 	i->tempFileName = NULL;
+	i->indirect = indirect;
 
 	ptrArrayAdd (inputSpecs, i);
 }
 
+
+static void loadIndirectTagFiles (struct inputSpec *inputSpec, ptrArray *inputSpecs)
+{
+	tagEntry pentry;
+	tagFileX *const fileX = openTags (inputSpec);
+
+	if (tagsFindPseudoTag (fileX->tagFile, &pentry, "!_READTAGS_INCLUDE",
+						   TAG_FULLMATCH) == TagSuccess)
+	{
+		addInputSpec (inputSpecs, pentry.file, true);
+
+		while (tagsNext (fileX->tagFile, &pentry) == TagSuccess)
+		{
+			if (pentry.name == NULL
+				|| pentry.name[0] != '!'
+				|| pentry.name[1] != '_')
+				break;
+			if (strcmp(pentry.name, "!_READTAGS_INCLUDE") != 0)
+				continue;
+			addInputSpec (inputSpecs, pentry.file, true);
+		}
+	}
+
+	deleteTagFileX (fileX);
+}
+
 extern int main (int argc, char **argv)
 {
 	int i;
@@ -817,12 +852,14 @@ extern int main (int argc, char **argv)
 				readOpts.matchOpts |= TAG_PARTIALMATCH;
 			else if (strcmp (optname, "list") == 0)
 				actionSpec.action |= ACTION_LIST;
+			else if (strcmp (optname, "list-included") == 0)
+				actionSpec.action |= ACTION_LIST_INCLUDED;
 			else if (strcmp (optname, "line-number") == 0)
 				printOpts.lineNumber = true;
 			else if (strcmp (optname, "tag-file") == 0)
 			{
 				if (i + 1 < argc)
-					addInputSpec (inputSpecs, argv[++i]);
+					addInputSpec (inputSpecs, argv[++i], false);
 				else
 					printUsage (stderr, 1);
 			}
@@ -951,16 +988,19 @@ extern int main (int argc, char **argv)
 					case 'l':
 						actionSpec.action |= ACTION_LIST;
 						break;
+					case 'L':
+						actionSpec.action |= ACTION_LIST_INCLUDED;
+						break;
 					case 'n': printOpts.lineNumber = true; break;
 					case 't':
 						if (arg [j+1] != '\0')
 						{
 							const char *tname = arg + j + 1;
-							addInputSpec (inputSpecs, tname);
+							addInputSpec (inputSpecs, tname, false);
 							j += strlen (tname);
 						}
 						else if (i + 1 < argc)
-							addInputSpec (inputSpecs, argv [++i]);
+							addInputSpec (inputSpecs, argv [++i], false);
 						else
 							printUsage(stderr, 1);
 						break;
@@ -1033,12 +1073,33 @@ extern int main (int argc, char **argv)
 	}
 
 	if (ptrArrayIsEmpty (inputSpecs))
-		addInputSpec (inputSpecs, "tags");
+		addInputSpec (inputSpecs, "tags", false);
+
+	unsigned int start = 0;
+	unsigned int end = ptrArrayCount (inputSpecs);
+	while (1)
+	{
+		for (unsigned int i = start; i < end; i++)
+		{
+			struct inputSpec *inputSpec = ptrArrayItem (inputSpecs, i);
+			loadIndirectTagFiles (inputSpec, inputSpecs);
+		}
+		start = end;
+		end = ptrArrayCount (inputSpecs);
+		if (start == end)
+			break;
+	}
 
 	for (unsigned int i = 0; i < ptrArrayCount (inputSpecs); i++)
 	{
 		struct inputSpec *inputSpec = ptrArrayItem (inputSpecs, i);
 
+		if (actionSpec.action & ACTION_LIST_INCLUDED)
+		{
+			if (inputSpec->indirect)
+				puts(inputSpec->tagFileName);
+		}
+
 		if (actionSpec.action & ACTION_LIST_PTAGS)
 		{
 			if (actionSpec.canonicalizing)