Add _without_gc functions to darray

These functions manipulate darray without the possibility of triggering
GC, which is used for places that cannot trigger GC. These functions
crash when the allocation fails.

1 files changed, 85 insertions, 29 deletions

diff --git a/darray.h b/darray.h
index db95c8b60e..b7ab0ab154 100644
--- a/darray.h
+++ b/darray.h
@@ -5,6 +5,8 @@
 #include <stddef.h>
 #include <stdlib.h>
 
+#include "internal/gc.h"
+
 // Type for a dynamic array. Use to declare a dynamic array.
 // It is a pointer so it fits in st_table nicely. Designed
 // to be fairly type-safe.
@@ -37,13 +39,21 @@
 //
 #define rb_darray_ref(ary, idx) (&((ary)->data[(idx)]))
 
-// Copy a new element into the array. ptr_to_ary is evaluated multiple times.
-//
-// void rb_darray_append(rb_darray(T) *ptr_to_ary, T element);
-//
-#define rb_darray_append(ptr_to_ary, element) do {  \
-    rb_darray_ensure_space((ptr_to_ary), sizeof(**(ptr_to_ary)), \
-                           sizeof((*(ptr_to_ary))->data[0])); \
+/* Copy a new element into the array. ptr_to_ary is evaluated multiple times.
+ *
+ * void rb_darray_append(rb_darray(T) *ptr_to_ary, T element);
+ */
+#define rb_darray_append(ptr_to_ary, element) \
+    rb_darray_append_impl(ptr_to_ary, element, rb_xrealloc_mul_add)
+
+#define rb_darray_append_without_gc(ptr_to_ary, element) \
+    rb_darray_append_impl(ptr_to_ary, element, rb_darray_realloc_mul_add_without_gc)
+
+#define rb_darray_append_impl(ptr_to_ary, element, realloc_func) do {  \
+    rb_darray_ensure_space((ptr_to_ary), \
+                           sizeof(**(ptr_to_ary)), \
+                           sizeof((*(ptr_to_ary))->data[0]), \
+                           realloc_func); \
     rb_darray_set(*(ptr_to_ary), \
                   (*(ptr_to_ary))->meta.size, \
                   (element)); \
@@ -55,28 +65,45 @@
 #define rb_darray_foreach(ary, idx_name, elem_ptr_var) \
     for (size_t idx_name = 0; idx_name < rb_darray_size(ary) && ((elem_ptr_var) = rb_darray_ref(ary, idx_name)); ++idx_name)
 
-// Make a dynamic array of a certain size. All bytes backing the elements are set to zero.
-//
-// Note that NULL is a valid empty dynamic array.
-//
-// void rb_darray_make(rb_darray(T) *ptr_to_ary, size_t size);
+// Iterate over valid indices in the array in a for loop
 //
+#define rb_darray_for(ary, idx_name) \
+    for (size_t idx_name = 0; idx_name < rb_darray_size(ary); ++idx_name)
+
+/* Make a dynamic array of a certain size. All bytes backing the elements are set to zero.
+ * Return 1 on success and 0 on failure.
+ *
+ * Note that NULL is a valid empty dynamic array.
+ *
+ * void rb_darray_make(rb_darray(T) *ptr_to_ary, size_t size);
+ */
 #define rb_darray_make(ptr_to_ary, size) \
     rb_darray_make_impl((ptr_to_ary), size, sizeof(**(ptr_to_ary)), \
-                         sizeof((*(ptr_to_ary))->data[0]))
+                         sizeof((*(ptr_to_ary))->data[0]), rb_xcalloc_mul_add)
 
-#define rb_darray_data_ptr(ary) ((ary)->data)
+#define rb_darray_make_without_gc(ptr_to_ary, size) \
+    rb_darray_make_impl((ptr_to_ary), size, sizeof(**(ptr_to_ary)), \
+                        sizeof((*(ptr_to_ary))->data[0]), rb_darray_calloc_mul_add_without_gc)
 
-// Set the size of the array to zero without freeing the backing memory.
-// Allows reusing the same array.
-//
-#define rb_darray_clear(ary) (ary->meta.size = 0)
+#define rb_darray_data_ptr(ary) ((ary)->data)
 
 typedef struct rb_darray_meta {
     size_t size;
     size_t capa;
 } rb_darray_meta_t;
 
+// Set the size of the array to zero without freeing the backing memory.
+// Allows reusing the same array.
+//
+static inline void
+rb_darray_clear(void *ary)
+{
+    rb_darray_meta_t *meta = ary;
+    if (meta) {
+        meta->size = 0;
+    }
+}
+
 // Get the size of the dynamic array.
 //
 static inline size_t
@@ -95,20 +122,52 @@ rb_darray_capa(const void *ary)
     return meta ? meta->capa : 0;
 }
 
-// Free the dynamic array.
-//
+/* Free the dynamic array. */
 static inline void
 rb_darray_free(void *ary)
 {
     rb_darray_meta_t *meta = ary;
-    ruby_sized_xfree(ary, meta->capa);
+    if (meta) ruby_sized_xfree(ary, meta->capa);
+}
+
+static inline void
+rb_darray_free_without_gc(void *ary)
+{
+    free(ary);
+}
+
+/* Internal function. Like rb_xcalloc_mul_add but does not trigger GC and does
+ * not check for overflow in arithmetic. */
+static inline void *
+rb_darray_calloc_mul_add_without_gc(size_t x, size_t y, size_t z)
+{
+    size_t size = (x * y) + z;
+
+    void *ptr = calloc(1, size);
+    if (ptr == NULL) rb_bug("rb_darray_calloc_mul_add_without_gc: failed");
+
+    return ptr;
+}
+
+/* Internal function. Like rb_xrealloc_mul_add but does not trigger GC and does
+ * not check for overflow in arithmetic. */
+static inline void *
+rb_darray_realloc_mul_add_without_gc(const void *orig_ptr, size_t x, size_t y, size_t z)
+{
+    size_t size = (x * y) + z;
+
+    void *ptr = realloc((void *)orig_ptr, size);
+    if (ptr == NULL) rb_bug("rb_darray_realloc_mul_add_without_gc: failed");
+
+    return ptr;
 }
 
 // Internal function
 // Ensure there is space for one more element.
 // Note: header_size can be bigger than sizeof(rb_darray_meta_t) when T is __int128_t, for example.
 static inline void
-rb_darray_ensure_space(void *ptr_to_ary, size_t header_size, size_t element_size)
+rb_darray_ensure_space(void *ptr_to_ary, size_t header_size, size_t element_size,
+                       void *(*realloc_mul_add_impl)(const void *, size_t, size_t, size_t))
 {
     rb_darray_meta_t **ptr_to_ptr_to_meta = ptr_to_ary;
     rb_darray_meta_t *meta = *ptr_to_ptr_to_meta;
@@ -118,9 +177,7 @@ rb_darray_ensure_space(void *ptr_to_ary, size_t header_size, size_t element_size
     // Double the capacity
     size_t new_capa = current_capa == 0 ? 1 : current_capa * 2;
 
-    rb_darray_meta_t *doubled_ary = rb_xrealloc_mul_add(meta, new_capa, element_size, header_size);
-    // rb_xrealloc functions guarantee that NULL is not returned
-    assert(doubled_ary != NULL);
+    rb_darray_meta_t *doubled_ary = realloc_mul_add_impl(meta, new_capa, element_size, header_size);
 
     if (meta == NULL) {
         // First allocation. Initialize size. On subsequence allocations
@@ -136,7 +193,8 @@ rb_darray_ensure_space(void *ptr_to_ary, size_t header_size, size_t element_size
 }
 
 static inline void
-rb_darray_make_impl(void *ptr_to_ary, size_t array_size, size_t header_size, size_t element_size)
+rb_darray_make_impl(void *ptr_to_ary, size_t array_size, size_t header_size, size_t element_size,
+                    void *(*calloc_mul_add_impl)(size_t, size_t, size_t))
 {
     rb_darray_meta_t **ptr_to_ptr_to_meta = ptr_to_ary;
     if (array_size == 0) {
@@ -144,9 +202,7 @@ rb_darray_make_impl(void *ptr_to_ary, size_t array_size, size_t header_size, siz
         return;
     }
 
-    rb_darray_meta_t *meta = rb_xcalloc_mul_add(array_size, element_size, header_size);
-    // rb_xcalloc functions guarantee that NULL is not returned
-    assert(meta != NULL);
+    rb_darray_meta_t *meta = calloc_mul_add_impl(array_size, element_size, header_size);
 
     meta->size = array_size;
     meta->capa = array_size;