Improve the `Allocator` interface to support returning `Allocator_Error` to allow for safer calls

Virtually all code (except for user-written custom allocators) should work as normal. Extra features will need to be added to make the current procedures support the `Allocator_Error` return value (akin to #optional_ok)

8 files changed, 116 insertions, 73 deletions

diff --git a/core/runtime/core.odin b/core/runtime/core.odin
index 8763b9b8b..05f7a1e57 100644
--- a/core/runtime/core.odin
+++ b/core/runtime/core.odin
@@ -252,7 +252,6 @@ Source_Code_Location :: struct {
 
 Assertion_Failure_Proc :: #type proc(prefix, message: string, loc: Source_Code_Location);
 
-
 // Allocation Stuff
 Allocator_Mode :: enum byte {
 	Alloc,
@@ -271,9 +270,16 @@ Allocator_Query_Info :: struct {
 	alignment: Maybe(int),
 }
 
+Allocator_Error :: enum byte {
+	None            = 0,
+	Out_Of_Memory   = 1,
+	Invalid_Pointer = 2,
+}
+
 Allocator_Proc :: #type proc(allocator_data: rawptr, mode: Allocator_Mode,
                              size, alignment: int,
-                             old_memory: rawptr, old_size: int, flags: u64 = 0, location: Source_Code_Location = #caller_location) -> rawptr;
+                             old_memory: rawptr, old_size: int,
+                             location: Source_Code_Location = #caller_location) -> ([]byte, Allocator_Error);
 Allocator :: struct {
 	procedure: Allocator_Proc,
 	data:      rawptr,
diff --git a/core/runtime/core_builtin.odin b/core/runtime/core_builtin.odin
index 9f6d1b35b..7446b496b 100644
--- a/core/runtime/core_builtin.odin
+++ b/core/runtime/core_builtin.odin
@@ -180,12 +180,14 @@ DEFAULT_RESERVE_CAPACITY :: 16;
 
 make_aligned :: proc($T: typeid/[]$E, auto_cast len: int, alignment: int, allocator := context.allocator, loc := #caller_location) -> T {
 	make_slice_error_loc(loc, len);
-	data := mem_alloc(size_of(E)*len, alignment, allocator, loc);
-	if data == nil && size_of(E) != 0 {
+	data, err := mem_alloc_bytes(size_of(E)*len, alignment, allocator, loc);
+	switch {
+	case err != nil:
+		return nil;
+	case data == nil && size_of(E) != 0:
 		return nil;
 	}
-	// mem_zero(data, size_of(E)*len);
-	s := Raw_Slice{data, len};
+	s := Raw_Slice{raw_data(data), len};
 	return transmute(T)s;
 }
 
@@ -449,15 +451,15 @@ reserve_dynamic_array :: proc(array: ^$T/[dynamic]$E, capacity: int, loc := #cal
 	new_size  := capacity * size_of(E);
 	allocator := a.allocator;
 
-	new_data := allocator.procedure(
+	new_data, err := allocator.procedure(
 		allocator.data, .Resize, new_size, align_of(E),
-		a.data, old_size, 0, loc,
+		a.data, old_size, loc,
 	);
-	if new_data == nil {
+	if new_data == nil || err != nil {
 		return false;
 	}
 
-	a.data = new_data;
+	a.data = raw_data(new_data);
 	a.cap = capacity;
 	return true;
 }
@@ -483,15 +485,15 @@ resize_dynamic_array :: proc(array: ^$T/[dynamic]$E, length: int, loc := #caller
 	new_size  := length * size_of(E);
 	allocator := a.allocator;
 
-	new_data := allocator.procedure(
+	new_data, err := allocator.procedure(
 		allocator.data, .Resize, new_size, align_of(E),
-		a.data, old_size, 0, loc,
+		a.data, old_size, loc,
 	);
-	if new_data == nil {
+	if new_data == nil || err != nil {
 		return false;
 	}
 
-	a.data = new_data;
+	a.data = raw_data(new_data);
 	a.len = length;
 	a.cap = length;
 	return true;
diff --git a/core/runtime/core_builtin_soa.odin b/core/runtime/core_builtin_soa.odin
index fea0d7305..d7de057d2 100644
--- a/core/runtime/core_builtin_soa.odin
+++ b/core/runtime/core_builtin_soa.odin
@@ -226,13 +226,14 @@ reserve_soa :: proc(array: ^$T/#soa[dynamic]$E, capacity: int, loc := #caller_lo
 
 	old_data := (^rawptr)(array)^;
 
-	new_data := array.allocator.procedure(
+	new_bytes, err := array.allocator.procedure(
 		array.allocator.data, .Alloc, new_size, max_align,
-		nil, old_size, 0, loc,
+		nil, old_size, loc,
 	);
-	if new_data == nil {
+	if new_bytes == nil || err != nil {
 		return false;
 	}
+	new_data := raw_data(new_bytes);
 
 
 	footer.cap = capacity;
@@ -256,9 +257,9 @@ reserve_soa :: proc(array: ^$T/#soa[dynamic]$E, capacity: int, loc := #caller_lo
 		new_offset += type.size * capacity;
 	}
 
-	array.allocator.procedure(
+	_, err = array.allocator.procedure(
 		array.allocator.data, .Free, 0, max_align,
-		old_data, old_size, 0, loc,
+		old_data, old_size, loc,
 	);
 
 	return true;
diff --git a/core/runtime/default_allocators.odin b/core/runtime/default_allocators.odin
index 03bc454d0..64229ec6c 100644
--- a/core/runtime/default_allocators.odin
+++ b/core/runtime/default_allocators.odin
@@ -5,8 +5,8 @@ when ODIN_DEFAULT_TO_NIL_ALLOCATOR || ODIN_OS == "freestanding" {
 
 	default_allocator_proc :: proc(allocator_data: rawptr, mode: mem.Allocator_Mode,
 	                               size, alignment: int,
-	                               old_memory: rawptr, old_size: int, flags: u64 = 0, loc := #caller_location) -> rawptr {
-		return nil;
+	                               old_memory: rawptr, old_size: int, loc := #caller_location) -> ([]byte, Allocator_Error) {
+		return nil, .None;
 	}
 
 	default_allocator :: proc() -> Allocator {
@@ -26,6 +26,13 @@ when ODIN_DEFAULT_TO_NIL_ALLOCATOR || ODIN_OS == "freestanding" {
 	}
 }
 
+@(private)
+byte_slice :: #force_inline proc "contextless" (data: rawptr, len: int) -> (res: []byte) {
+	r := (^Raw_Slice)(&res);
+	r.data, r.len = data, len;
+	return;
+}
+
 
 DEFAULT_TEMP_ALLOCATOR_BACKING_SIZE: int : #config(DEFAULT_TEMP_ALLOCATOR_BACKING_SIZE, 1<<22);
 
@@ -35,7 +42,7 @@ Default_Temp_Allocator :: struct {
 	curr_offset:        int,
 	prev_allocation:    rawptr,
 	backup_allocator:   Allocator,
-	leaked_allocations: [dynamic]rawptr,
+	leaked_allocations: [dynamic][]byte,
 }
 
 default_temp_allocator_init :: proc(s: ^Default_Temp_Allocator, size: int, backup_allocator := context.allocator) {
@@ -51,7 +58,7 @@ default_temp_allocator_destroy :: proc(s: ^Default_Temp_Allocator) {
 		return;
 	}
 	for ptr in s.leaked_allocations {
-		free(ptr, s.backup_allocator);
+		free(raw_data(ptr), s.backup_allocator);
 	}
 	delete(s.leaked_allocations);
 	delete(s.data, s.backup_allocator);
@@ -60,7 +67,7 @@ default_temp_allocator_destroy :: proc(s: ^Default_Temp_Allocator) {
 
 default_temp_allocator_proc :: proc(allocator_data: rawptr, mode: Allocator_Mode,
                                     size, alignment: int,
-                                    old_memory: rawptr, old_size: int, flags: u64 = 0, loc := #caller_location) -> rawptr {
+                                    old_memory: rawptr, old_size: int, loc := #caller_location) -> ([]byte, Allocator_Error) {
 
 	s := (^Default_Temp_Allocator)(allocator_data);
 
@@ -84,7 +91,7 @@ default_temp_allocator_proc :: proc(allocator_data: rawptr, mode: Allocator_Mode
 			s.prev_allocation = rawptr(ptr);
 			offset := int(ptr - start);
 			s.curr_offset = offset + size;
-			return rawptr(ptr);
+			return byte_slice(rawptr(ptr), size), .None;
 
 		case size <= len(s.data):
 			start := uintptr(raw_data(s.data));
@@ -94,7 +101,7 @@ default_temp_allocator_proc :: proc(allocator_data: rawptr, mode: Allocator_Mode
 			s.prev_allocation = rawptr(ptr);
 			offset := int(ptr - start);
 			s.curr_offset = offset + size;
-			return rawptr(ptr);
+			return byte_slice(rawptr(ptr), size), .None;
 		}
 		a := s.backup_allocator;
 		if a.procedure == nil {
@@ -102,11 +109,14 @@ default_temp_allocator_proc :: proc(allocator_data: rawptr, mode: Allocator_Mode
 			s.backup_allocator = a;
 		}
 
-		ptr := mem_alloc(size, alignment, a, loc);
+		data, err := mem_alloc_bytes(size, alignment, a, loc);
+		if err != nil {
+			return data, err;
+		}
 		if s.leaked_allocations == nil {
-			s.leaked_allocations = make([dynamic]rawptr, a);
+			s.leaked_allocations = make([dynamic][]byte, a);
 		}
-		append(&s.leaked_allocations, ptr);
+		append(&s.leaked_allocations, data);
 
 		// TODO(bill): Should leaks be notified about?
 		if logger := context.logger; logger.lowest_level <= .Warning {
@@ -115,11 +125,11 @@ default_temp_allocator_proc :: proc(allocator_data: rawptr, mode: Allocator_Mode
 			}
 		}
 
-		return ptr;
+		return data, .None;
 
 	case .Free:
 		if old_memory == nil {
-			return nil;
+			return nil, .None;
 		}
 
 		start := uintptr(raw_data(s.data));
@@ -129,30 +139,32 @@ default_temp_allocator_proc :: proc(allocator_data: rawptr, mode: Allocator_Mode
 		if s.prev_allocation == old_memory {
 			s.curr_offset = int(uintptr(s.prev_allocation) - start);
 			s.prev_allocation = nil;
-			return nil;
+			return nil, .None;
 		}
 
 		if start <= old_ptr && old_ptr < end {
 			// NOTE(bill): Cannot free this pointer but it is valid
-			return nil;
+			return nil, .None;
 		}
 
 		if len(s.leaked_allocations) != 0 {
-			for ptr, i in s.leaked_allocations {
+			for data, i in s.leaked_allocations {
+				ptr := raw_data(data);
 				if ptr == old_memory {
 					free(ptr, s.backup_allocator);
 					ordered_remove(&s.leaked_allocations, i);
-					return nil;
+					return nil, .None;
 				}
 			}
 		}
-		panic("invalid pointer passed to default_temp_allocator");
+		return nil, .Invalid_Pointer;
+		// panic("invalid pointer passed to default_temp_allocator");
 
 	case .Free_All:
 		s.curr_offset = 0;
 		s.prev_allocation = nil;
-		for ptr in s.leaked_allocations {
-			free(ptr, s.backup_allocator);
+		for data in s.leaked_allocations {
+			free(raw_data(data), s.backup_allocator);
 		}
 		clear(&s.leaked_allocations);
 
@@ -163,26 +175,28 @@ default_temp_allocator_proc :: proc(allocator_data: rawptr, mode: Allocator_Mode
 		if old_memory == s.prev_allocation && old_ptr & uintptr(alignment)-1 == 0 {
 			if old_ptr+uintptr(size) < end {
 				s.curr_offset = int(old_ptr-begin)+size;
-				return old_memory;
+				return byte_slice(old_memory, size), .None;
 			}
 		}
-		ptr := default_temp_allocator_proc(allocator_data, .Alloc, size, alignment, old_memory, old_size, flags, loc);
-		mem_copy(ptr, old_memory, old_size);
-		default_temp_allocator_proc(allocator_data, .Free, 0, alignment, old_memory, old_size, flags, loc);
-		return ptr;
+		ptr, err := default_temp_allocator_proc(allocator_data, .Alloc, size, alignment, old_memory, old_size, loc);
+		if err == .None {
+			copy(ptr, byte_slice(old_memory, old_size));
+			_, err = default_temp_allocator_proc(allocator_data, .Free, 0, alignment, old_memory, old_size, loc);
+		}
+		return ptr, err;
 
 	case .Query_Features:
 		set := (^Allocator_Mode_Set)(old_memory);
 		if set != nil {
 			set^ = {.Alloc, .Free, .Free_All, .Resize, .Query_Features};
 		}
-		return set;
+		return nil, nil;
 
 	case .Query_Info:
-		return nil;
+		return nil, .None;
 	}
 
-	return nil;
+	return nil, .None;
 }
 
 default_temp_allocator :: proc(allocator: ^Default_Temp_Allocator) -> Allocator {
diff --git a/core/runtime/dynamic_array_internal.odin b/core/runtime/dynamic_array_internal.odin
index 55289bbe4..340f3be5e 100644
--- a/core/runtime/dynamic_array_internal.odin
+++ b/core/runtime/dynamic_array_internal.odin
@@ -29,10 +29,13 @@ __dynamic_array_reserve :: proc(array_: rawptr, elem_size, elem_align: int, cap:
 	new_size  := cap * elem_size;
 	allocator := array.allocator;
 
-	new_data := allocator.procedure(allocator.data, .Resize, new_size, elem_align, array.data, old_size, 0, loc);
+	new_data, err := allocator.procedure(allocator.data, .Resize, new_size, elem_align, array.data, old_size, loc);
+	if err != nil {
+		return false;
+	}
 	if new_data != nil || elem_size == 0 {
-		array.data = new_data;
-		array.cap = cap;
+		array.data = raw_data(new_data);
+		array.cap = min(cap, len(new_data)/elem_size);
 		return true;
 	}
 	return false;
diff --git a/core/runtime/dynamic_map_internal.odin b/core/runtime/dynamic_map_internal.odin
index 8b63e6a7b..aff3b9859 100644
--- a/core/runtime/dynamic_map_internal.odin
+++ b/core/runtime/dynamic_map_internal.odin
@@ -173,8 +173,8 @@ __slice_resize :: proc(array_: ^$T/[]$E, new_count: int, allocator: Allocator, l
 	old_size := array.len*size_of(T);
 	new_size := new_count*size_of(T);
 
-	new_data := mem_resize(array.data, old_size, new_size, align_of(T), allocator, loc);
-	if new_data == nil {
+	new_data, err := mem_resize(array.data, old_size, new_size, align_of(T), allocator, loc);
+	if new_data == nil || err != nil {
 		return false;
 	}
 	array.data = new_data;
diff --git a/core/runtime/internal.odin b/core/runtime/internal.odin
index 5381ee276..51f478a67 100644
--- a/core/runtime/internal.odin
+++ b/core/runtime/internal.odin
@@ -159,6 +159,16 @@ mem_copy_non_overlapping :: proc "contextless" (dst, src: rawptr, len: int) -> r
 
 DEFAULT_ALIGNMENT :: 2*align_of(rawptr);
 
+mem_alloc_bytes :: #force_inline proc(size: int, alignment: int = DEFAULT_ALIGNMENT, allocator := context.allocator, loc := #caller_location) -> ([]byte, Allocator_Error) {
+	if size == 0 {
+		return nil, nil;
+	}
+	if allocator.procedure == nil {
+		return nil, nil;
+	}
+	return allocator.procedure(allocator.data, .Alloc, size, alignment, nil, 0, loc);
+}
+
 mem_alloc :: #force_inline proc(size: int, alignment: int = DEFAULT_ALIGNMENT, allocator := context.allocator, loc := #caller_location) -> rawptr {
 	if size == 0 {
 		return nil;
@@ -166,36 +176,43 @@ mem_alloc :: #force_inline proc(size: int, alignment: int = DEFAULT_ALIGNMENT, a
 	if allocator.procedure == nil {
 		return nil;
 	}
-	return allocator.procedure(allocator.data, .Alloc, size, alignment, nil, 0, 0, loc);
+	data, err := allocator.procedure(allocator.data, .Alloc, size, alignment, nil, 0, loc);
+	_ = err;
+	return raw_data(data);
 }
 
-mem_free :: #force_inline proc(ptr: rawptr, allocator := context.allocator, loc := #caller_location) {
+mem_free :: #force_inline proc(ptr: rawptr, allocator := context.allocator, loc := #caller_location) -> Allocator_Error {
 	if ptr == nil {
-		return;
+		return .None;
 	}
 	if allocator.procedure == nil {
-		return;
+		return .None;
 	}
-	allocator.procedure(allocator.data, .Free, 0, 0, ptr, 0, 0, loc);
+	_, err := allocator.procedure(allocator.data, .Free, 0, 0, ptr, 0, loc);
+	return err;
 }
 
-mem_free_all :: #force_inline proc(allocator := context.allocator, loc := #caller_location) {
+mem_free_all :: #force_inline proc(allocator := context.allocator, loc := #caller_location) -> (err: Allocator_Error) {
 	if allocator.procedure != nil {
-		allocator.procedure(allocator.data, .Free_All, 0, 0, nil, 0, 0, loc);
+		_, err = allocator.procedure(allocator.data, .Free_All, 0, 0, nil, 0, loc);
 	}
+	return;
 }
 
-mem_resize :: #force_inline proc(ptr: rawptr, old_size, new_size: int, alignment: int = DEFAULT_ALIGNMENT, allocator := context.allocator, loc := #caller_location) -> rawptr {
+mem_resize :: #force_inline proc(ptr: rawptr, old_size, new_size: int, alignment: int = DEFAULT_ALIGNMENT, allocator := context.allocator, loc := #caller_location) -> (new_ptr: rawptr, err: Allocator_Error) {
+	new_data: []byte;
 	switch {
 	case allocator.procedure == nil:
-		return nil;
+		return;
 	case new_size == 0:
-		allocator.procedure(allocator.data, .Free, 0, 0, ptr, 0, 0, loc);
-		return nil;
+		new_data, err = allocator.procedure(allocator.data, .Free, 0, 0, ptr, 0, loc);
 	case ptr == nil:
-		return allocator.procedure(allocator.data, .Alloc, new_size, alignment, nil, 0, 0, loc);
+		new_data, err = allocator.procedure(allocator.data, .Alloc, new_size, alignment, nil, 0, loc);
+	case:
+		new_data, err = allocator.procedure(allocator.data, .Resize, new_size, alignment, ptr, old_size, loc);
 	}
-	return allocator.procedure(allocator.data, .Resize, new_size, alignment, ptr, old_size, 0, loc);
+	new_ptr = raw_data(new_data);
+	return;
 }
 memory_equal :: proc "contextless" (a, b: rawptr, n: int) -> bool {
 	return memory_compare(a, b, n) == 0;
diff --git a/core/runtime/os_specific_windows.odin b/core/runtime/os_specific_windows.odin
index ad01196ed..0cf9d28f4 100644
--- a/core/runtime/os_specific_windows.odin
+++ b/core/runtime/os_specific_windows.odin
@@ -88,7 +88,7 @@ heap_free :: proc "contextless" (ptr: rawptr) {
 
 default_allocator_proc :: proc(allocator_data: rawptr, mode: Allocator_Mode,
                                size, alignment: int,
-                               old_memory: rawptr, old_size: int, flags: u64 = 0, loc := #caller_location) -> rawptr {
+                               old_memory: rawptr, old_size: int, loc := #caller_location) -> ([]byte, Allocator_Error) {
 
 	//
 	// NOTE(tetra, 2020-01-14): The heap doesn't respect alignment.
@@ -97,7 +97,7 @@ default_allocator_proc :: proc(allocator_data: rawptr, mode: Allocator_Mode,
 	// the pointer we return to the user.
 	//
 
-	aligned_alloc :: proc "contextless" (size, alignment: int, old_ptr: rawptr = nil) -> rawptr {
+	aligned_alloc :: proc "contextless" (size, alignment: int, old_ptr: rawptr = nil) -> ([]byte, Allocator_Error) {
 		a := max(alignment, align_of(rawptr));
 		space := size + a - 1;
 
@@ -114,13 +114,13 @@ default_allocator_proc :: proc(allocator_data: rawptr, mode: Allocator_Mode,
 		aligned_ptr := (ptr - 1 + uintptr(a)) & -uintptr(a);
 		diff := int(aligned_ptr - ptr);
 		if (size + diff) > space {
-			return nil;
+			return nil, .Out_Of_Memory;
 		}
 
 		aligned_mem = rawptr(aligned_ptr);
 		ptr_offset((^rawptr)(aligned_mem), -1)^ = allocated_mem;
 
-		return aligned_mem;
+		return byte_slice(aligned_mem, size), nil;
 	}
 
 	aligned_free :: proc "contextless" (p: rawptr) {
@@ -129,9 +129,9 @@ default_allocator_proc :: proc(allocator_data: rawptr, mode: Allocator_Mode,
 		}
 	}
 
-	aligned_resize :: proc "contextless" (p: rawptr, old_size: int, new_size: int, new_alignment: int) -> rawptr {
+	aligned_resize :: proc "contextless" (p: rawptr, old_size: int, new_size: int, new_alignment: int) -> ([]byte, Allocator_Error) {
 		if p == nil {
-			return nil;
+			return nil, nil;
 		}
 		return aligned_alloc(new_size, new_alignment, p);
 	}
@@ -157,13 +157,13 @@ default_allocator_proc :: proc(allocator_data: rawptr, mode: Allocator_Mode,
 		if set != nil {
 			set^ = {.Alloc, .Free, .Resize, .Query_Features};
 		}
-		return set;
+		return nil, nil;
 
 	case .Query_Info:
-		return nil;
+		return nil, nil;
 	}
 
-	return nil;
+	return nil, nil;
 }
 
 default_allocator :: proc() -> Allocator {