internal: Simplify STREQ_NULLABLE

Our STREQ_NULLABLE and STRNEQ_NULLABLE macros are too
complicated. This was a result of some broken version of gcc.
However, that is long gone and therefore we can simplify the
macros.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>

src/internal.h

@@ -92,9 +92,9 @@
 # define STRSKIP(a, b) (STRPREFIX(a, b) ? (a) + strlen(b) : NULL)
 
 # define STREQ_NULLABLE(a, b)                           \
-    ((a) ? (b) && STREQ((a) ? (a) : "", (b) ? (b) : "") : !(b))
+    ((a) ? (b) && STREQ((a), (b)) : !(b))
 # define STRNEQ_NULLABLE(a, b)                          \
-    ((a) ? !(b) || STRNEQ((a) ? (a) : "", (b) ? (b) : "") : !!(b))
+    ((a) ? !(b) || STRNEQ((a), (b)) : !!(b))
 
 # define NUL_TERMINATE(buf) do { (buf)[sizeof(buf)-1] = '\0'; } while (0)
 # define ARRAY_CARDINALITY(Array) (sizeof(Array) / sizeof(*(Array)))

tests/virstringtest.c

@@ -34,6 +34,53 @@
 
 VIR_LOG_INIT("tests.stringtest");
 
+struct testStreqData {
+    const char *a;
+    const char *b;
+};
+
+static int testStreq(const void *args)
+{
+    const struct testStreqData *data = args;
+    int ret = -1;
+    bool equal = true;
+    bool streq_rv, strneq_rv;
+    size_t i;
+
+    if ((size_t) data->a ^ (size_t) data->b)
+        equal = false;
+    if (data->a && data->b) {
+        for (i = 0; data->a[i] != '\0'; i++) {
+            if (data->b[i] == '\0' ||
+                data->a[i] != data->b[i]) {
+                equal = false;
+                break;
+            }
+        }
+    }
+
+    streq_rv = STREQ_NULLABLE(data->a, data->b);
+    strneq_rv = STRNEQ_NULLABLE(data->a, data->b);
+
+    if (streq_rv != equal) {
+        virFilePrintf(stderr,
+                      "STREQ not working correctly. Expected %d got %d",
+                      (int) equal, (int) streq_rv);
+        goto cleanup;
+    }
+
+    if (strneq_rv == equal) {
+        virFilePrintf(stderr,
+                      "STRNEQ not working correctly. Expected %d got %d",
+                      (int) equal, (int) strneq_rv);
+        goto cleanup;
+    }
+
+    ret = 0;
+ cleanup:
+    return ret;
+}
+
 struct testSplitData {
     const char *string;
     const char *delim;
@@ -651,6 +698,20 @@ mymain(void)
 {
     int ret = 0;
 
+#define TEST_STREQ(aa, bb)                                              \
+    do {                                                                \
+        struct testStreqData streqData = {.a = aa, .b = bb};            \
+        if (virTestRun("Streq", testStreq, &streqData) < 0)             \
+            ret = -1;                                                   \
+    } while (0)
+
+    TEST_STREQ("hello", "world");
+    TEST_STREQ(NULL, NULL);
+    TEST_STREQ(NULL, "");
+    TEST_STREQ("", NULL);
+    TEST_STREQ("", "");
+    TEST_STREQ("hello", "hello");
+
 #define TEST_SPLIT(str, del, max, toks)                                 \
     do {                                                                \
         struct testSplitData splitData = {                              \