minigbm: refactor driver helpers

1. frontends access the driver via drv.h only
2. the renamed drv_helpers and drv_array_helpers are for driver only
3. remove extern "C" from drv_helpers.h given not exposed to gralloc
4. remove all redundant includes for those helpers

BUG=b:199524294
TEST=CQ and gralloc builds on aosp

Change-Id: I3f4d33076a6a8161804f1b7c26950ff5496507e9
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/minigbm/+/3195651
Tested-by: Yiwei Zhang <zzyiwei@chromium.org>
Reviewed-by: Chia-I Wu <olv@google.com>
Commit-Queue: Yiwei Zhang <zzyiwei@chromium.org>

drv_array_helpers.c

@@ -0,0 +1,104 @@
+/*
+ * Copyright 2017 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#include "drv_array_helpers.h"
+
+#include <assert.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "util.h"
+
+struct drv_array {
+	void **items;
+	uint32_t size;
+	uint32_t item_size;
+	uint32_t allocations;
+};
+
+struct drv_array *drv_array_init(uint32_t item_size)
+{
+	struct drv_array *array;
+
+	array = calloc(1, sizeof(*array));
+	if (!array)
+		return NULL;
+
+	/* Start with a power of 2 number of allocations. */
+	array->allocations = 2;
+	array->items = calloc(array->allocations, sizeof(*array->items));
+	if (!array->items) {
+		free(array);
+		return NULL;
+	}
+
+	array->item_size = item_size;
+	return array;
+}
+
+void *drv_array_append(struct drv_array *array, void *data)
+{
+	void *item;
+
+	if (array->size >= array->allocations) {
+		void **new_items = NULL;
+		array->allocations *= 2;
+		new_items = realloc(array->items, array->allocations * sizeof(*array->items));
+		assert(new_items);
+		array->items = new_items;
+	}
+
+	item = calloc(1, array->item_size);
+	memcpy(item, data, array->item_size);
+	array->items[array->size] = item;
+	array->size++;
+	return item;
+}
+
+void drv_array_remove(struct drv_array *array, uint32_t idx)
+{
+	uint32_t i;
+
+	assert(array);
+	assert(idx < array->size);
+
+	free(array->items[idx]);
+	array->items[idx] = NULL;
+
+	for (i = idx + 1; i < array->size; i++)
+		array->items[i - 1] = array->items[i];
+
+	array->size--;
+	if ((DIV_ROUND_UP(array->allocations, 2) > array->size) && array->allocations > 2) {
+		void **new_items = NULL;
+		array->allocations = DIV_ROUND_UP(array->allocations, 2);
+		new_items = realloc(array->items, array->allocations * sizeof(*array->items));
+		assert(new_items);
+		array->items = new_items;
+	}
+}
+
+void *drv_array_at_idx(struct drv_array *array, uint32_t idx)
+{
+	assert(idx < array->size);
+	return array->items[idx];
+}
+
+uint32_t drv_array_size(struct drv_array *array)
+{
+	return array->size;
+}
+
+void drv_array_destroy(struct drv_array *array)
+{
+	uint32_t i;
+
+	for (i = 0; i < array->size; i++)
+		free(array->items[i]);
+
+	free(array->items);
+	free(array);
+}