readtags: add an optoin (-X) for emitting an aggregate tag file

  $ ./readtags -t podman.tags -t glibc.tags -t coreutils832.tags -X | tee tags
  !_READTAGS_INCLUDE	podman.tags	//
  !_READTAGS_INCLUDE	glibc.tags	//
  !_READTAGS_INCLUDE	coreutils832.tags	//
  !_TAG_FILE_FORMAT	2	//
  !_TAG_FILE_SORTED	1	//
  !_TAG_OUTPUT_EXCMD	pattern	//
  !_TAG_OUTPUT_FILESEP	slash	//
  !_TAG_OUTPUT_MODE	u-ctags	//
  !_TAG_OUTPUT_VERSION	0.0	/current.age/
  !_TAG_PATTERN_LENGTH_LIMIT	0	//
  !_TAG_PROC_CWD	/home/yamato/var/ctags-github	//
  !_TAG_PROGRAM_AUTHOR	Universal Ctags Team	//
  !_TAG_PROGRAM_NAME	readtags	/with -X option/
  !_TAG_PROGRAM_URL	https://ctags.io/	/official site/
  !_TAG_PROGRAM_VERSION	0.0.0	/TODO/
  $ ./readtags -A rootful
  rootful	/home/yamato/var/podman/pkg/machine/e2e/config_init_test.go	/^	rootful            bool$/
  rootful	/home/yamato/var/podman/pkg/machine/e2e/config_set_test.go	/^	rootful            bool$/
  $ ./readtags -A rootless
  rootless	/home/yamato/var/podman/pkg/rootless/rootless.go	/^package rootless$/
  rootless	/home/yamato/var/podman/pkg/rootless/rootless_freebsd.go	/^package rootless$/
  rootless	/home/yamato/var/podman/pkg/rootless/rootless_linux.go	/^package rootless$/
  rootless	/home/yamato/var/podman/pkg/rootless/rootless_test.go	/^package rootless$/
  rootless	/home/yamato/var/podman/pkg/rootless/rootless_unsupported.go	/^package rootless$/
  rootless	/home/yamato/var/podman/vendor/github.com/containers/image/v5/internal/rootless/rootless.go	/^package rootless$/

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

Author: masatake

extra-cmds/readtags-cmd.c

@@ -24,6 +24,8 @@
 #include <stdio.h>		/* stderr */
 #include <stdbool.h>
 
+#include <unistd.h>
+
 typedef struct sReadOption {
 	bool sortOverride;
 	sortType sortMethod;
@@ -56,6 +58,7 @@ struct actionSpec {
 		ACTION_LIST = 1 << 1,
 		ACTION_LIST_PTAGS = 1 << 2,
 		ACTION_LIST_INCLUDED = 1 << 3,
+		ACTION_AGGREGATE = 1 << 4,
 	} action;
 	const char *name;			/* for ACTION_FIND */
 	bool canonicalizing;
@@ -609,6 +612,8 @@ static const char *const Usage =
 	"        List pseudo tags.\n"
 	"    -L | --list-included\n"
 	"        List included tag files.\n"
+	"    -X | --generate-aggregate-tag-file\n"
+	"        Generate an aggregate file includes tag files specified with -t option.\n"
 	"Options:\n"
 	"    -d | --debug\n"
 	"        Turn on debugging output.\n"
@@ -764,6 +769,42 @@ static void loadIndirectTagFiles (struct inputSpec *inputSpec, ptrArray *inputSp
 	deleteTagFileX (fileX);
 }
 
+static void printMustPseudoTag(tagPrintOptions *opts, FILE *fp,
+							   const char *name, const char *file,const char *pattern)
+{
+	tagEntry e;
+
+	memset (&e, 0, sizeof (e));
+
+	e.name = name;
+	e.file = file;
+	e.address.pattern = pattern;
+	tagsPrintPseudoTag (&e, opts, NULL, fp);
+}
+
+static void printMustPseudoTags(tagPrintOptions *opts, FILE *fp)
+{
+	char buf[PATH_MAX];
+	if (!getcwd(buf, sizeof(buf)))
+	{
+		fprintf(stderr, "Failed to get the current working directory\n");
+		exit (1);
+	}
+
+	printMustPseudoTag(opts, fp, "!_TAG_FILE_FORMAT",	"2",	"//");
+	printMustPseudoTag(opts, fp, "!_TAG_FILE_SORTED",	"1",	"//");
+	printMustPseudoTag(opts, fp, "!_TAG_OUTPUT_EXCMD",	"pattern", "//");
+	printMustPseudoTag(opts, fp, "!_TAG_OUTPUT_FILESEP", "slash",	"//");
+	printMustPseudoTag(opts, fp, "!_TAG_OUTPUT_MODE",	"u-ctags", "//");
+	printMustPseudoTag(opts, fp, "!_TAG_OUTPUT_VERSION", "0.0", "/current.age/");
+	printMustPseudoTag(opts, fp, "!_TAG_PATTERN_LENGTH_LIMIT", "0", "//");
+	printMustPseudoTag(opts, fp, "!_TAG_PROC_CWD", buf, "//");
+	printMustPseudoTag(opts, fp, "!_TAG_PROGRAM_AUTHOR", "Universal Ctags Team", "//");
+	printMustPseudoTag(opts, fp, "!_TAG_PROGRAM_NAME", "readtags",	"/with -X option/");
+	printMustPseudoTag(opts, fp, "!_TAG_PROGRAM_URL", "https://ctags.io/", "/official site/");
+	printMustPseudoTag(opts, fp, "!_TAG_PROGRAM_VERSION", "0.0.0", "/TODO/");
+}
+
 extern int main (int argc, char **argv)
 {
 	int i;
@@ -901,6 +942,8 @@ extern int main (int argc, char **argv)
 				actionSpec.canonicalizing = true;
 				actionSpec.canon.absoluteOnly = false;
 			}
+			else if (strcmp (optname, "generate-aggregate-tag-file") == 0)
+				actionSpec.action |= ACTION_AGGREGATE;
 #ifdef READTAGS_DSL
 			else if (strcmp (optname, "filter") == 0)
 			{
@@ -1022,6 +1065,9 @@ extern int main (int argc, char **argv)
 						actionSpec.canonicalizing = true;
 						actionSpec.canon.absoluteOnly = false;
 						break;
+					case 'X':
+						actionSpec.action |= ACTION_AGGREGATE;
+						break;
 #ifdef READTAGS_DSL
 					case 'Q':
 						if (i + 1 == argc)
@@ -1075,6 +1121,23 @@ extern int main (int argc, char **argv)
 	if (ptrArrayIsEmpty (inputSpecs))
 		addInputSpec (inputSpecs, "tags", false);
 
+	if (actionSpec.action & ACTION_AGGREGATE)
+	{
+		tagEntry e;
+		for (unsigned int i = 0; i < ptrArrayCount (inputSpecs); i++)
+		{
+			struct inputSpec *inputSpec = ptrArrayItem (inputSpecs, i);
+			memset (&e, 0, sizeof (e));
+			e.name = "!_READTAGS_INCLUDE";
+			e.file = inputSpec->tagFileName;
+			e.address.pattern = "//";
+			tagsPrintPseudoTag (&e, &printOpts, NULL, stdout);
+		}
+
+		printMustPseudoTags (&printOpts, stdout);
+		goto out;
+	}
+
 	unsigned int start = 0;
 	unsigned int end = ptrArrayCount (inputSpecs);
 	while (1)
@@ -1124,6 +1187,7 @@ extern int main (int argc, char **argv)
 		}
 	}
 
+ out:
 	ptrArrayDelete (inputSpecs);
 
 #ifdef READTAGS_DSL