// Copyright 2018 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.

//! Manages system resources that can be allocated to VMs and their devices.

use std::ops::RangeInclusive;

use remain::sorted;
use serde::{Deserialize, Serialize};
use thiserror::Error;

pub use crate::system_allocator::{MemRegion, MmioType, SystemAllocator, SystemAllocatorConfig};

pub mod address_allocator;
mod system_allocator;

/// Used to tag SystemAllocator allocations.
#[derive(Debug, Eq, PartialEq, Hash, Copy, Clone, Serialize, Deserialize)]
pub enum Alloc {
    /// An anonymous resource allocation.
    /// Should only be instantiated through `SystemAllocator::get_anon_alloc()`.
    /// Avoid using these. Instead, use / create a more descriptive Alloc variant.
    Anon(usize),
    /// A PCI BAR region with associated bus, device, function and bar numbers.
    PciBar { bus: u8, dev: u8, func: u8, bar: u8 },
    /// GPU render node region.
    GpuRenderNode,
    /// Pmem device region with associated device index.
    PmemDevice(usize),
    /// pstore region.
    Pstore,
    /// A PCI bridge window with associated bus, dev, function.
    PciBridgeWindow { bus: u8, dev: u8, func: u8 },
    /// A PCI bridge prefetch window with associated bus, dev, function.
    PciBridgePrefetchWindow { bus: u8, dev: u8, func: u8 },
    /// File-backed memory mapping.
    FileBacked(u64),
    /// virtio vhost user queue with queue id
    VvuQueue(u8),
}

#[sorted]
#[derive(Error, Debug, Eq, PartialEq)]
pub enum Error {
    #[error("Allocation cannot have size of 0")]
    AllocSizeZero,
    #[error("Pool alignment must be a power of 2")]
    BadAlignment,
    #[error("Alloc does not exist: {0:?}")]
    BadAlloc(Alloc),
    #[error("Alloc already exists: {0:?}")]
    ExistingAlloc(Alloc),
    #[error("Invalid Alloc: {0:?}")]
    InvalidAlloc(Alloc),
    #[error("IO port out of range: base:{0} size:{1}")]
    IOPortOutOfRange(u64, u64),
    #[error("Platform MMIO address range not specified")]
    MissingPlatformMMIOAddresses,
    #[error("No IO address range specified")]
    NoIoAllocator,
    #[error("Out of bounds")]
    OutOfBounds,
    #[error("Out of space")]
    OutOfSpace,
    #[error("base={base} + size={size} overflows")]
    PoolOverflow { base: u64, size: u64 },
    #[error("Pool cannot have size of 0")]
    PoolSizeZero,
    #[error("Overlapping region base={base} size={size}")]
    RegionOverlap { base: u64, size: u64 },
}

pub type Result<T> = std::result::Result<T, Error>;

/// Computes the length of a RangeInclusive value. Returns None
/// if the range is 0..=u64::MAX.
pub fn range_inclusive_len(r: &RangeInclusive<u64>) -> Option<u64> {
    (r.end() - r.start()).checked_add(1)
}