[api] Simplify debug allocator and fix handling of 0 size realloc.

Author: travisdoor

lib/bl/api/std/debug_allocator/debug_allocator.bl

@@ -1,31 +1,3 @@
-// =================================================================================================
-// bl
-//
-// File:   debug_allocator.bl
-// Author: Martin Dorazil
-// Date:   18/9/20
-//
-// Copyright 2020 Martin Dorazil
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-// SOFTWARE.
-// =================================================================================================
-
 //! # Debug Allocator
 //!
 //! `#import "std/debug_allocator"`
@@ -194,23 +166,28 @@ Meta :: struct {
 
 handler :: fn (dbgalloc: *DebugAllocator, operation: AllocOp, ptr: *u8, size: usize, alignment: usize, file: string_view, line: s32) (mem: *u8, err: Error) {
 	using AllocOp;
+	mutex_lock(&dbgalloc.mutex);
+	defer mutex_unlock(&dbgalloc.mutex);
+
 	switch operation {
 		ALLOCATE {
-			mem, err :: alloc(size, alignment, dbgalloc.allocator);
-			if err { return mem, err; }
+			mem :: alloc(size, alignment, dbgalloc.allocator) catch return null, $;
 			add_allocation(dbgalloc, mem, size, alignment, file, line);
-			return mem, err;
+			return mem, OK;
 		}
 		REALLOCATE {
 			if ptr {
 				_, previous_alignment :: remove_allocation(dbgalloc, ptr);
 				if previous_alignment != alignment {
 					panic("Alignment of reallocated memory block must be the same as the previous one!"
-						  " Previous alignment is %B and current is %B.", previous_alignment, alignment);
+					" Previous alignment is %B and current is %B.", previous_alignment, alignment);
 				}
 			}
-			mem, err :: realloc(ptr, size, alignment, dbgalloc.allocator);
-			if err { return mem, err; }
+			if size == 0 {
+				free(ptr, dbgalloc.allocator);
+				return null, OK;
+			}
+			mem :: realloc(ptr, size, alignment, dbgalloc.allocator) catch return null, $;
 			add_allocation(dbgalloc, mem, size, alignment, file, line);
 			return mem, OK;
 		}
@@ -234,9 +211,7 @@ handler :: fn (dbgalloc: *DebugAllocator, operation: AllocOp, ptr: *u8, size: us
 }
 
 add_allocation :: fn (dbgalloc: *DebugAllocator, ptr: *u8, size: usize, alignment: usize, file: string_view, line: s32) {
-	mutex_lock(&dbgalloc.mutex);
-	defer mutex_unlock(&dbgalloc.mutex);
-
+	assert(ptr);
 	dbgalloc.serial += 1;
 	if dbgalloc.break_on == dbgalloc.serial { debugbreak; }
 
@@ -251,8 +226,7 @@ add_allocation :: fn (dbgalloc: *DebugAllocator, ptr: *u8, size: usize, alignmen
 }
 
 remove_allocation :: fn (dbgalloc: *DebugAllocator, ptr: *u8) (size: usize, alignment: usize) {
-	mutex_lock(&dbgalloc.mutex);
-	defer mutex_unlock(&dbgalloc.mutex);
+	assert(ptr);
 	value :: tbl_lookup_ptr(&dbgalloc.alloc_table, ptr);
 	if !value {
 		panic("Attempt to free already freed or unallocated memory on address %!", ptr);