#ifndef MANGO_VM_REGION_H_
#define MANGO_VM_REGION_H_

#include <mango/object.h>
#include <mango/pmap.h>
#include <mango/vm.h>

#define VM_REGION_NAME_MAX        64

#define VM_REGION_ANY_MAP_ADDRESS ((virt_addr_t) - 1)

struct vm_region;
struct vm_object;

enum vm_region_entry_type {
	VM_REGION_ENTRY_NONE = 0,
	VM_REGION_ENTRY_REGION,
	VM_REGION_ENTRY_MAPPING,
};

struct vm_region_entry {
	struct btree_node e_node;
	struct vm_region_entry *e_parent;
	enum vm_region_entry_type e_type;
	/* absolute virtual address of the entry */
	virt_addr_t e_base_address;
	/* size of the entry in bytes */
	size_t e_size;
};

struct vm_region_mapping {
	struct vm_region_entry m_entry;
	struct vm_object *m_object;

	/* used to link to  vm_object->vo_mappings */
	struct queue_entry m_object_entry;

	enum vm_prot m_prot;
	/* offset in bytes to the start of the object data that was mapped */
	off_t m_object_offset;
};

struct vm_region {
	struct object vr_base;
	struct vm_region_entry vr_entry;

	char vr_name[VM_REGION_NAME_MAX];

	/* btree of struct vm_region_entry.
	 * sibling entries cannot overlap each other, and child entries must
	 * be entirely contained within their immediate parent entry. */
	struct btree vr_entries;

	/* memory protection restriction mask.
	 * any mapping in this region, or any of its children, cannot use
	 * protection flags that are not set in this mask.
	 * for example, if VM_PROT_EXEC is /not/ set here, no mapping
	 * can be created in this region or any child region with VM_PROT_EXEC
	 * set. */
	enum vm_prot vr_prot;

	/* the physical address space in which mappings in this region (and
	 * its children) are created */
	pmap_t vr_pmap;
};

extern kern_status_t vm_region_type_init(void);

extern kern_status_t vm_region_create(
	struct vm_region *parent,
	const char *name,
	virt_addr_t base,
	size_t len,
	enum vm_prot prot,
	struct vm_region **out);

/* find the child region that has jurisdiction over the specified virtual
 * address. returns the lowest-nested region that covers the specified virtual
 * address. */
extern struct vm_region *vm_region_find_child(
	struct vm_region *region,
	virt_addr_t addr);

/* find the child region that has jurisdiction over the specified virtual
 * address area. returns the lowest-nested region that covers the specified
 * virtual address area. the area must be fully contained within a region, with
 * no partial overlaps. if an area is covered by multiple regions, or is only
 * partially within a region, returns NULL. */
extern struct vm_region *vm_region_find_child_for_area(
	struct vm_region *region,
	virt_addr_t addr,
	size_t len);
extern struct vm_region_mapping *vm_region_find_mapping(
	struct vm_region *region,
	virt_addr_t addr);

extern kern_status_t vm_region_map_object(
	struct vm_region *region,
	virt_addr_t map_address,
	struct vm_object *object,
	off_t object_offset,
	size_t length,
	enum vm_prot prot,
	virt_addr_t *out);

/* returns true if the memory area defined by [base, base+len] contains:
 *  - no child regions
 *  - no vm_object mappings
 * if any child regions or mappings exist in the memory area, returns false.
 * if the memory area exceeds the bounds of the region, returns false.
 */
extern bool vm_region_is_area_free(
	const struct vm_region *region,
	virt_addr_t base,
	size_t len);

extern kern_status_t vm_region_demand_map(
	struct vm_region *region,
	virt_addr_t addr,
	enum pmap_fault_flags flags);

extern void vm_region_dump(struct vm_region *region, int depth);

DEFINE_OBJECT_LOCK_FUNCTION(vm_region, vr_base)

#endif