libctf, include: new functions for looking up enumerators

Three new functions for looking up the enum type containing a given
enumeration constant, and optionally that constant's value.

The simplest, ctf_lookup_enumerator, looks up a root-visible enumerator by
name in one dict: if the dict contains multiple such constants (which is
possible for dicts created by older versions of the libctf deduplicator),
ECTF_DUPLICATE is returned.

The next simplest, ctf_lookup_enumerator_next, is an iterator which returns
all enumerators with a given name in a given dict, whether root-visible or
not.

The most elaborate, ctf_arc_lookup_enumerator_next, finds all
enumerators with a given name across all dicts in an entire CTF archive,
whether root-visible or not, starting looking in the shared parent dict;
opened dicts are cached (as with all other ctf_arc_*lookup functions) so
that repeated use does not incur repeated opening costs.

All three of these return enumerator values as int64_t: unfortunately, API
compatibility concerns prevent us from doing the same with the other older
enum-related functions, which all return enumerator constant values as ints.
We may be forced to add symbol-versioning compatibility aliases that fix the
other functions in due course, bumping the soname for platforms that do not
support such things.

ctf_arc_lookup_enumerator_next is implemented as a nested ctf_archive_next
iterator, and inside that, a nested ctf_lookup_enumerator_next iterator
within each dict.  To aid in this, add support to ctf_next_t iterators for
iterators that are implemented in terms of two simultaneous nested iterators
at once.  (It has always been possible for callers to use as many nested or
semi-overlapping ctf_next_t iterators as they need, which is one of the
advantages of this style over the _iter style that calls a function for each
thing iterated over: the iterator change here permits *ctf_next_t iterators
themselves* to be implemented by iterating using multiple other iterators as
part of their internal operation, transparently to the caller.)

Also add a testcase that tests all these functions (which is fairly easy
because ctf_arc_lookup_enumerator_next is implemented in terms of
ctf_lookup_enumerator_next) in addition to enumeration addition in
ctf_open()ed dicts, ctf_add_enumerator duplicate enumerator addition, and
conflicting enumerator constant deduplication.

include/
	* ctf-api.h (ctf_lookup_enumerator): New.
	(ctf_lookup_enumerator_next): Likewise.
	(ctf_arc_lookup_enumerator_next): Likewise.

libctf/
	* libctf.ver: Add them.
	* ctf-impl.h (ctf_next_t) <ctn_next_inner>: New.
	* ctf-util.c (ctf_next_copy): Copy it.
        (ctf_next_destroy): Destroy it.
	* ctf-lookup.c (ctf_lookup_enumerator): New.
	(ctf_lookup_enumerator_next): New.
	* ctf-archive.c (ctf_arc_lookup_enumerator_next): New.
	* testsuite/libctf-lookup/enumerator-iteration.*: New test.
	* testsuite/libctf-lookup/enum-ctf-2.c: New test CTF, used by the
	  above.

3 files changed, 191 insertions, 0 deletions

diff --git a/libctf/testsuite/libctf-lookup/enum-ctf-2.c b/libctf/testsuite/libctf-lookup/enum-ctf-2.c
new file mode 100644
index 0000000..39c9865
--- /dev/null
+++ b/libctf/testsuite/libctf-lookup/enum-ctf-2.c
@@ -0,0 +1,6 @@
+enum e { ENUMSAMPLE_1 = 6, ENUMSAMPLE_2 = 7 };
+
+enum ie2 { IENUMSAMPLE2_1 = -10, IENUMSAMPLE2_2 };
+
+enum e baz;
+enum ie2 quux;
diff --git a/libctf/testsuite/libctf-lookup/enumerator-iteration.c b/libctf/testsuite/libctf-lookup/enumerator-iteration.c
new file mode 100644
index 0000000..e46dad6
--- /dev/null
+++ b/libctf/testsuite/libctf-lookup/enumerator-iteration.c
@@ -0,0 +1,168 @@
+/* Test enumerator iteration and querying.  Because
+   ctf_arc_lookup_enumerator_next uses ctf_lookup_enumerator_next internally, we
+   only need to test the former.  */
+
+#include "config.h"
+#include <ctf-api.h>
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static void
+print_constants (ctf_archive_t *ctf, const char *name)
+{
+  ctf_next_t *i = NULL;
+  int err;
+  ctf_dict_t *fp;
+  ctf_id_t type;
+  int64_t val;
+
+  while ((type = ctf_arc_lookup_enumerator_next (ctf, name, &i,
+						 &val, &fp, &err)) != CTF_ERR)
+    {
+      char *foo;
+
+      printf ("%s in %s has value %i\n", name,
+	      foo = ctf_type_aname (fp, type), val);
+      free (foo);
+
+      ctf_dict_close (fp);
+    }
+  if (err != ECTF_NEXT_END)
+    {
+      fprintf (stderr, "iteration failed: %s\n", ctf_errmsg (err));
+      exit (1);
+    }
+}
+
+int
+main (int argc, char *argv[])
+{
+  ctf_archive_t *ctf;
+  ctf_dict_t *fp;
+  int err;
+  ctf_id_t type;
+  ctf_next_t *i = NULL;
+  const char *name;
+  int64_t val;
+  int counter = 0;
+
+  if (argc != 2)
+    {
+      fprintf (stderr, "Syntax: %s PROGRAM\n", argv[0]);
+      exit(1);
+    }
+
+  if ((ctf = ctf_open (argv[1], NULL, &err)) == NULL)
+    goto open_err;
+
+  /* Look for all instances of ENUMSAMPLE2_1, and add some new enums to all
+     dicts found, to test dynamic enum iteration as well as static.
+
+     Add two enums with a different name and constants to any that should
+     already be there (one hidden), and one with the same constants, but hidden,
+     to test ctf_lookup_enumerator_next()'s multiple-lookup functionality and
+     ctf_lookup_enumerator() in the presence of hidden types.  */
+
+  printf ("First iteration: addition of enums.\n");
+  while ((type = ctf_arc_lookup_enumerator_next (ctf, "IENUMSAMPLE2_2", &i,
+						 &val, &fp, &err)) != CTF_ERR)
+    {
+      char *foo;
+
+      printf ("IENUMSAMPLE2_2 in %s has value %i\n",
+	      foo = ctf_type_aname (fp, type), val);
+      free (foo);
+
+      if ((type = ctf_add_enum (fp, CTF_ADD_ROOT, "ie3")) == CTF_ERR)
+	goto enum_add_err;
+
+      if (ctf_add_enumerator (fp, type, "DYNADD", counter += 10) < 0)
+	goto enumerator_add_err;
+      if (ctf_add_enumerator (fp, type, "DYNADD2", counter += 10) < 0)
+	goto enumerator_add_err;
+
+      /* Make sure that overlapping enumerator addition fails as it should.  */
+
+      if (ctf_add_enumerator (fp, type, "IENUMSAMPLE2_2", 666) >= 0
+	  || ctf_errno (fp) != ECTF_DUPLICATE)
+	fprintf (stderr, "Duplicate enumerator addition did not fail as it ought to\n");
+
+      if ((type = ctf_add_enum (fp, CTF_ADD_NONROOT, "ie4_hidden")) == CTF_ERR)
+	goto enum_add_err;
+
+      if (ctf_add_enumerator (fp, type, "DYNADD3", counter += 10) < 0)
+	goto enumerator_add_err;
+      if (ctf_add_enumerator (fp, type, "DYNADD4", counter += 10) < 0)
+	goto enumerator_add_err;
+
+      if ((type = ctf_add_enum (fp, CTF_ADD_NONROOT, "ie3_hidden")) == CTF_ERR)
+	goto enum_add_err;
+
+      if (ctf_add_enumerator (fp, type, "DYNADD", counter += 10) < 0)
+	goto enumerator_add_err;
+      if (ctf_add_enumerator (fp, type, "DYNADD2", counter += 10) < 0)
+	goto enumerator_add_err;
+
+      /* Look them up via ctf_lookup_enumerator.  */
+
+      if (ctf_lookup_enumerator (fp, "DYNADD", &val) == CTF_ERR)
+	goto enumerator_lookup_err;
+      printf ("direct lookup: DYNADD value: %i\n", (int) val);
+
+      if ((type = ctf_lookup_enumerator (fp, "DYNADD3", &val) != CTF_ERR) ||
+	  ctf_errno (fp) != ECTF_NOENUMNAM)
+	{
+	  if (type != CTF_ERR)
+	    {
+	      char *foo;
+	      printf ("direct lookup: hidden lookup did not return ECTF_NOENUMNAM but rather %i in %s\n",
+		      val, foo = ctf_type_aname (fp, type));
+	      free (foo);
+	    }
+	  else
+	    printf ("direct lookup: hidden lookup did not return ECTF_NOENUMNAM but rather %s\n",
+		    ctf_errno (fp));
+	}
+
+      ctf_dict_close (fp);
+    }
+  if (err != ECTF_NEXT_END)
+    {
+      fprintf (stderr, "iteration failed: %s\n", ctf_errmsg (err));
+      return 1;
+    }
+
+  /* Look for (and print out) some enumeration constants.  */
+
+  printf ("Second iteration: printing of enums.\n");
+
+  print_constants (ctf, "ENUMSAMPLE_1");
+  print_constants (ctf, "IENUMSAMPLE_1");
+  print_constants (ctf, "ENUMSAMPLE_2");
+  print_constants (ctf, "DYNADD");
+  print_constants (ctf, "DYNADD3");
+
+  ctf_close (ctf);
+
+  printf ("All done.\n");
+
+  return 0;
+
+ open_err:
+  fprintf (stderr, "%s: cannot open: %s\n", argv[0], ctf_errmsg (err));
+  return 1;
+ enum_add_err:
+  fprintf (stderr, "Cannot add enum to dict \"%s\": %s\n",
+	   ctf_cuname (fp) ? ctf_cuname (fp) : "(null: parent)", ctf_errmsg (ctf_errno (fp)));
+  return 1;
+ enumerator_add_err:
+  fprintf (stderr, "Cannot add enumerator to dict \"%s\": %s\n",
+	   ctf_cuname (fp) ? ctf_cuname (fp) : "(null: parent)", ctf_errmsg (ctf_errno (fp)));
+  return 1;
+ enumerator_lookup_err:
+  fprintf (stderr, "Cannot look up enumerator in dict \"%s\": %s\n",
+	   ctf_cuname (fp) ? ctf_cuname (fp) : "(null: parent)", ctf_errmsg (ctf_errno (fp)));
+  return 1;
+}
diff --git a/libctf/testsuite/libctf-lookup/enumerator-iteration.lk b/libctf/testsuite/libctf-lookup/enumerator-iteration.lk
new file mode 100644
index 0000000..0c3cbfb
--- /dev/null
+++ b/libctf/testsuite/libctf-lookup/enumerator-iteration.lk
@@ -0,0 +1,17 @@
+# lookup: enumerator-iteration.c
+# source: enum-ctf.c
+# source: enum-ctf-2.c
+# link: on
+First iteration: addition of enums.
+IENUMSAMPLE2_2 in enum ie2 has value -9
+direct lookup: DYNADD value: 10
+Second iteration: printing of enums.
+ENUMSAMPLE_1 in enum e has value 6
+ENUMSAMPLE_1 in enum e has value 0
+IENUMSAMPLE_1 in enum ie has value -10
+ENUMSAMPLE_2 in enum e has value 7
+ENUMSAMPLE_2 in enum e has value 1
+DYNADD in enum ie3 has value 10
+DYNADD in enum ie3_hidden has value 50
+DYNADD3 in enum ie4_hidden has value 30
+All done.