From 9979407567cb42df9873f83a4dca779073759296 Mon Sep 17 00:00:00 2001
From: Panu Matilainen <pmatilai@redhat.com>
Date: Fri, 23 May 2008 10:31:45 +0300
Subject: [PATCH] Add rpmtdSetTag() method for setting (or changing) container
 tag + type - permit change on non-empty container to compatible type to allow
 things like     headerGet(h, RPMTAG_FILENAMES, td, HEADERGET_EXT);    
 rpmtdSetTag(td, RPMTAG_OLDFILENAMES);     headerPut(h, td,
 HEADERPUT_DEFAULT); - empty container can be set to any valid type

---
 lib/rpmtd.c | 28 ++++++++++++++++++++++++++++
 lib/rpmtd.h | 10 ++++++++++
 2 files changed, 38 insertions(+)

diff --git a/lib/rpmtd.c b/lib/rpmtd.c
index daac145..9114059 100644
--- a/lib/rpmtd.c
+++ b/lib/rpmtd.c
@@ -191,6 +191,34 @@ char *rpmtdFormat(rpmtd td, rpmtdFormats fmt, const char *errmsg)
     return str;
 }
 
+int rpmtdSetTag(rpmtd td, rpmTag tag)
+{
+    assert(td != NULL);
+    rpmTagType newtype = rpmTagGetType(tag);
+    int rc = 0;
+
+    /* 
+     * Sanity checks: 
+     * - is the new tag valid at all
+     * - if changing tag of non-empty container, require matching type 
+     */
+    if (newtype == RPM_NULL_TYPE)
+	goto exit;
+
+    if (td->data || td->count > 0) {
+	if (rpmTagGetType(td->tag) != rpmTagGetType(tag)) {
+	    goto exit;
+	}
+    } 
+
+    td->tag = tag;
+    td->type = newtype & RPM_MASK_TYPE;
+    rc = 1;
+    
+exit:
+    return rc;
+}
+
 int rpmtdFromArgv(rpmtd td, rpmTag tag, ARGV_t argv)
 {
     int count = argvCount(argv);
diff --git a/lib/rpmtd.h b/lib/rpmtd.h
index 30d28c0..bc368fa 100644
--- a/lib/rpmtd.h
+++ b/lib/rpmtd.h
@@ -172,6 +172,16 @@ typedef enum rpmtdFormats_e {
 char *rpmtdFormat(rpmtd td, rpmtdFormats fmt, const char *errmsg);
 
 /** \ingroup rpmtd
+ * Set container tag and type.
+ * For empty container, any valid tag can be set. If the container has
+ * data, changing is only permitted to tag of same type. 
+ * @param td		Tag data container
+ * @param tag		New tag
+ * @return		1 on success, 0 on error
+ */
+int rpmtdSetTag(rpmtd td, rpmTag tag);
+
+/** \ingroup rpmtd
  * Construct tag container from ARGV_t array.
  * Tag type is checked to be of string array type and array is checked
  * to be non-empty.
-- 
2.7.4