// Copyright 2020 The Fuchsia Authors
//
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file or at
// https://opensource.org/licenses/MIT

#include "phys/allocation.h"

#include <lib/fitx/result.h>
#include <lib/memalloc/pool.h>
#include <zircon/assert.h>

#include <fbl/no_destructor.h>
#include <ktl/array.h>
#include <ktl/byte.h>
#include <ktl/move.h>
#include <ktl/string_view.h>
#include <phys/arch/arch-allocation.h>
#include <phys/main.h>

#include <ktl/enforce.h>

// Global memory allocation book-keeping.
memalloc::Pool& Allocation::GetPool() {
  // Use fbl::NoDestructor to avoid generation of static destructors,
  // which fails in the phys environment.
  static fbl::NoDestructor<memalloc::Pool> allocator;
  return *allocator;
}

void Allocation::Init(ktl::span<memalloc::Range> mem_ranges,
                      ktl::span<memalloc::Range> special_ranges) {
  auto& pool = Allocation::GetPool();
  ktl::array ranges{mem_ranges, special_ranges};
  // kAllocationMinAddr is defined in arch-allocation.h.
  auto init_result = kAllocationMinAddr  // ktl::nullopt if don't care.
                         ? pool.Init(ranges, *kAllocationMinAddr)
                         : pool.Init(ranges);
  ZX_ASSERT(init_result.is_ok());
}

// This is where actual allocation happens.
// The returned object is default-constructed if it fails.
Allocation Allocation::New(fbl::AllocChecker& ac, memalloc::Type type, size_t size,
                           size_t alignment, ktl::optional<uint64_t> min_addr,
                           ktl::optional<uint64_t> max_addr) {
  Allocation alloc;
  fitx::result<fitx::failed, uint64_t> result =
      GetPool().Allocate(type, size, alignment, min_addr, max_addr);
  ac.arm(size, result.is_ok());
  if (result.is_ok()) {
    alloc.data_ = {reinterpret_cast<ktl::byte*>(result.value()), size};
    alloc.alignment_ = alignment;
  }
  return alloc;
}

// This is where actual deallocation happens.  The destructor just calls this.
void Allocation::reset() {
  if (!data_.empty()) {
    auto result = GetPool().Free(reinterpret_cast<uint64_t>(data_.data()), data_.size());
    ZX_ASSERT(result.is_ok());
    data_ = {};
  }
}

void Allocation::Resize(fbl::AllocChecker& ac, size_t new_size) {
  ZX_ASSERT(!data_.empty());
  ZX_ASSERT(new_size > 0);

  if (new_size == size_bytes()) {
    return;
  }

  const memalloc::Range range = {
      .addr = reinterpret_cast<uint64_t>(get()),
      .size = size_bytes(),
      .type = type_,
  };
  auto result = GetPool().Resize(range, new_size, alignment_);
  ac.arm(new_size, result.is_ok());
  if (result.is_ok()) {
    auto* new_addr = reinterpret_cast<ktl::byte*>(ktl::move(result).value());
    if (new_addr != get()) {
      memmove(new_addr, get(), size_bytes());
    }
    data_ = {new_addr, new_size};
  }
}