Resurrect parseExpressionString()

This essentially reverts commit 398df91274be4e6a9fae0cbbc59f95f6e490ed0f,
with a few changes to account for other changes that happened in the
meanwhile and establish a single point of return.

(cherry picked from commit 8936960d7f15e728b60fa1ea73b0d8a6eff97ad6)

2 files changed, 53 insertions, 0 deletions

diff --git a/build/expression.c b/build/expression.c
index f0d4dcf5c..4e2e79e46 100644
--- a/build/expression.c
+++ b/build/expression.c
@@ -714,3 +714,47 @@ exit:
   valueFree(v);
   return result;
 }
+
+char * parseExpressionString(const char *expr)
+{
+  struct _parseState state;
+  char *result = NULL;
+  Value v;
+
+  DEBUG(printf("parseExprString(?, '%s')\n", expr));
+
+  /* Initialize the expression parser state. */
+  state.p = state.str = xstrdup(expr);
+  state.nextToken = 0;
+  state.tokenValue = NULL;
+  (void) rdToken(&state);
+
+  /* Parse the expression. */
+  v = doLogical(&state);
+  if (!v)
+    goto exit;
+
+  /* If the next token is not TOK_EOF, we have a syntax error. */
+  if (state.nextToken != TOK_EOF) {
+    rpmlog(RPMLOG_ERR, _("syntax error in expression\n"));
+    goto exit;
+  }
+
+  DEBUG(valueDump("parseExprString:", v, stdout));
+
+  switch (v->type) {
+  case VALUE_TYPE_INTEGER: {
+    rasprintf(&result, "%d", v->data.i);
+  } break;
+  case VALUE_TYPE_STRING:
+    result = xstrdup(v->data.s);
+    break;
+  default:
+    break;
+  }
+
+exit:
+  state.str = _free(state.str);
+  valueFree(v);
+  return result;
+}
diff --git a/build/rpmbuild_internal.h b/build/rpmbuild_internal.h
index f3c8b5658..04901596a 100644
--- a/build/rpmbuild_internal.h
+++ b/build/rpmbuild_internal.h
@@ -410,6 +410,15 @@ RPM_GNUC_INTERNAL
 int parseExpressionBoolean(const char * expr);
 
 /** \ingroup rpmbuild
+ * Evaluate string expression.
+ * @param expr		expression to parse
+ * @return
+ */
+RPM_GNUC_INTERNAL
+char * parseExpressionString(const char * expr);
+
+
+/** \ingroup rpmbuild
  * Run a build script, assembled from spec file scriptlet section.
  *
  * @param spec		spec file control structure