Replace rpmhash with STL unordered_map in headerformat cache

A notable difference is that we're now storing the rpmtd structs
themselves in the hash, rather than pointers to them.

A minor side-cleanup is that headerGet() does not return data on failure
so there's no need to free anything in that case.

lib/headerfmt.c

@@ -4,6 +4,8 @@
 
 #include "system.h"
 
+#include <unordered_map>
+
 #include <stdarg.h>
 #include <rpm/header.h>
 #include <rpm/rpmtag.h>
@@ -61,15 +63,6 @@ struct sprintfToken_s {
  } u;
 };
 
-#define HASHTYPE tagCache
-#define HTKEYTYPE rpmTagVal
-#define HTDATATYPE rpmtd
-#include "rpmhash.H"
-#include "rpmhash.C"
-#undef HASHTYPE
-#undef HTKEYTYPE
-#undef HTDATATYPE
-
 typedef struct headerSprintfArgs_s *headerSprintfArgs;
 
 struct xformat_s {
@@ -87,7 +80,7 @@ struct headerSprintfArgs_s {
  Header h;
  char * fmt;
  const char * errmsg;
- tagCache cache;
+ std::unordered_map<rpmTagVal,rpmtd_s> cache;
  sprintfToken format;
  HeaderIterator hi;
  char * val;
@@ -723,12 +716,6 @@ static int parseExpression(headerSprintfArgs hsa, sprintfToken token,
  return 0;
 }
 
-static rpmtd getCached(tagCache cache, rpmTagVal tag)
-{
- rpmtd *res = NULL;
- return tagCacheGetEntry(cache, tag, &res, NULL, NULL) ? res[0] : NULL;
-}
-
 /**
  * Do headerGet() just once for given tag, cache results.
  * @param hsa headerSprintf args
@@ -742,13 +729,15 @@ static rpmtd getData(headerSprintfArgs hsa, rpmTagVal tag)
 {
  rpmtd td = NULL;
 
- if (!(td = getCached(hsa->cache, tag))) {
- td = rpmtdNew();
- if (!headerGet(hsa->h, tag, td, hsa->hgflags)) {
-  rpmtdFree(td);
+ auto it = hsa->cache.find(tag);
+ if (it == hsa->cache.end()) {
+ struct rpmtd_s tds;
+ if (!headerGet(hsa->h, tag, &tds, hsa->hgflags))
  return NULL;
- }
- tagCacheAddEntry(hsa->cache, tag, td);
+ auto val = hsa->cache.insert({tag, tds}).first;
+ td = &val->second;
+ } else {
+ td = &it->second;
  }
 
  return td;
@@ -910,31 +899,19 @@ static char * singleSprintf(headerSprintfArgs hsa, sprintfToken token,
  return (hsa->val + hsa->vallen);
 }
 
-static int tagCmp(rpmTagVal a, rpmTagVal b)
-{
- return (a != b);
-}
-
-static unsigned int tagId(rpmTagVal tag)
-{
- return tag;
-}
-
 char * headerFormat(Header h, const char * fmt, errmsg_t * errmsg) 
 {
- struct headerSprintfArgs_s hsa;
+ struct headerSprintfArgs_s hsa {};
  sprintfToken nextfmt;
  sprintfTag tag;
 
- memset(&hsa, 0, sizeof(hsa));
  hsa.h = headerLink(h);
  hsa.fmt = xstrdup(fmt);
  hsa.errmsg = NULL;
 
  if (parseFormat(&hsa, hsa.fmt, &hsa.format, &hsa.numTokens, NULL, PARSER_BEGIN))
  goto exit;
 
- hsa.cache = tagCacheCreate(128, tagId, tagCmp, NULL, rpmtdFree);
  hsa.val = xstrdup("");
 
  tag =
@@ -968,7 +945,8 @@ char * headerFormat(Header h, const char * fmt, errmsg_t * errmsg)
  if (hsa.val != NULL && hsa.vallen < hsa.alloced)
  hsa.val = xrealloc(hsa.val, hsa.vallen+1); 
 
- hsa.cache = tagCacheFree(hsa.cache);
+ for (auto & val : hsa.cache)
+ rpmtdFreeData(&val.second);
  hsa.format = freeFormat(hsa.format, hsa.numTokens);
 
 exit: