Fixup API to get closer to a libjq

jv_alloc.c

@@ -2,11 +2,89 @@
 #include <stdio.h>
 #include "jv_alloc.h"
 
+struct nomem_handler {
+    jv_nomem_handler_f handler;
+    void *data;
+};
+
+#ifndef USE_PTHREAD_KEY
+#ifdef _MSC_VER
+static __declspec(thread) struct nomem_handler nomem_handler;
+#else
+static __thread struct nomem_handler nomem_handler;
+#endif
+
+void jv_nomem_handler(jv_nomem_handler_f handler, void *data) {
+  nomem_handler.handler = handler;
+}
+
+static void memory_exhausted() {
+  if (nomem_handler.handler)
+    nomem_handler.handler(nomem_handler.data); // Maybe handler() will longjmp() to safety
+  // Or not
+  fprintf(stderr, "error: cannot allocate memory\n");
+  abort();
+}
+#else
+#ifdef HAVE_PTHREAD_KEY_CREATE
+#include <pthread.h>
+
+pthread_key_t nomem_handler_key;
+pthread_once_t mem_once = PTHREAD_ONCE_INIT;
+
+static void tsd_init(void) {
+  if (pthread_key_create(&nomem_handler_key, NULL) != 0) {
+    fprintf(stderr, "error: cannot create thread specific key");
+    abort();
+  }
+}
+
+void jv_nomem_handler(jv_nomem_handler_f handler, void *data) {
+  pthread_once(&mem_once, tsd_init); // cannot fail
+  struct nomem_handler *nomem_handler = calloc(1, sizeof (nomem_handler));
+  if (nomem_handler == NULL) {
+    handler(data);
+    fprintf(stderr, "error: cannot allocate memory\n");
+    abort();
+  }
+  nomem_handler.handler = handler;
+  nomem_handler.data = data;
+  if (pthread_setspecific(nomem_handler_key, nomem_handler) != 0) {
+    handler(data);
+    fprintf(stderr, "error: cannot set thread specific data");
+    abort();
+  }
+}
+
+static void memory_exhausted() {
+  jv_nomem_handler_f handler;
+
+  pthread_once(&mem_once, tsd_init);
+  handler = pthread_getspecific(nomem_handler_key);
+  if (handler)
+    handler(); // Maybe handler() will longjmp() to safety
+  // Or not
+  fprintf(stderr, "error: cannot allocate memory\n");
+  abort();
+}
+
+#else
+
+static struct nomem_handler nomem_handler;
+void jv_nomem_handler(jv_nomem_handler_f handler, void *data) {
+  nomem_handler.handler = handler;
+  nomem_handler.data = data;
+}
+
 static void memory_exhausted() {
   fprintf(stderr, "error: cannot allocate memory\n");
   abort();
 }
 
+#endif /* HAVE_PTHREAD_KEY_CREATE */
+#endif /* !USE_PTHREAD_KEY */
+
+
 void* jv_mem_alloc(size_t sz) {
   void* p = malloc(sz);
   if (!p) {
@@ -15,6 +93,10 @@ void* jv_mem_alloc(size_t sz) {
   return p;
 }
 
+void* jv_mem_alloc_unguarded(size_t sz) {
+  return malloc(sz);
+}
+
 void jv_mem_free(void* p) {
   free(p);
 }