// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
 * Ceph - scalable distributed file system
 *
 * Copyright (C) 2012 Inktank
 *
 * This is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License version 2.1, as published by the Free Software
 * Foundation.  See file COPYING.
 *
 */

#include "Striper.h"

#include "include/types.h"
#include "include/buffer.h"
#include "osd/OSDMap.h"

#include "common/config.h"
#include "common/debug.h"

#define dout_subsys ceph_subsys_striper
#undef dout_prefix
#define dout_prefix *_dout << "striper "

using std::make_pair;
using std::map;
using std::pair;

using ceph::bufferlist;

namespace {

object_t format_oid(const char* object_format, uint64_t object_no) {
  char buf[strlen(object_format) + 32];
  snprintf(buf, sizeof(buf), object_format, (long long unsigned)object_no);
  return object_t(buf);
}

struct OrderByObject {
  constexpr bool operator()(uint64_t object_no,
                            const striper::LightweightObjectExtent& rhs) const {
    return object_no < rhs.object_no;
  }
  constexpr bool operator()(const striper::LightweightObjectExtent& lhs,
                            uint64_t object_no) const {
    return lhs.object_no < object_no;
  }
};

template <typename I>
void add_partial_sparse_result(
    CephContext *cct,
    std::map<uint64_t, std::pair<ceph::buffer::list, uint64_t> >* partial,
    uint64_t* total_intended_len, bufferlist& bl, I* it, const I& end_it,
    uint64_t* bl_off, uint64_t tofs, uint64_t tlen) {
  ldout(cct, 30) << " be " << tofs << "~" << tlen << dendl;

  auto& s = *it;
  while (tlen > 0) {
    ldout(cct, 20) << "  t " << tofs << "~" << tlen
                   << " bl has " << bl.length()
                   << " off " << *bl_off << dendl;
    if (s == end_it) {
      ldout(cct, 20) << "  s at end" << dendl;
      auto& r = (*partial)[tofs];
      r.second = tlen;
      *total_intended_len += r.second;
      break;
    }

    ldout(cct, 30) << "  s " << s->first << "~" << s->second << dendl;

    // skip zero-length extent
    if (s->second == 0) {
      ldout(cct, 30) << "  s len 0, skipping" << dendl;
      ++s;
      continue;
    }

    if (s->first > *bl_off) {
      // gap in sparse read result
      pair<bufferlist, uint64_t>& r = (*partial)[tofs];
      size_t gap = std::min<size_t>(s->first - *bl_off, tlen);
      ldout(cct, 20) << "  s gap " << gap << ", skipping" << dendl;
      r.second = gap;
      *total_intended_len += r.second;
      *bl_off += gap;
      tofs += gap;
      tlen -= gap;
      if (tlen == 0) {
        continue;
      }
    }

    ceph_assert(s->first <= *bl_off);
    size_t left = (s->first + s->second) - *bl_off;
    size_t actual = std::min<size_t>(left, tlen);

    if (actual > 0) {
      ldout(cct, 20) << "  s has " << actual << ", copying" << dendl;
      pair<bufferlist, uint64_t>& r = (*partial)[tofs];
      bl.splice(0, actual, &r.first);
      r.second = actual;
      *total_intended_len += r.second;
      *bl_off += actual;
      tofs += actual;
      tlen -= actual;
    }
    if (actual == left) {
      ldout(cct, 30) << "  s advancing" << dendl;
      ++s;
    }
  }
}

} // anonymous namespace

void Striper::file_to_extents(CephContext *cct, const char *object_format,
			      const file_layout_t *layout,
			      uint64_t offset, uint64_t len,
			      uint64_t trunc_size,
			      std::vector<ObjectExtent>& extents,
			      uint64_t buffer_offset)
{
  striper::LightweightObjectExtents lightweight_object_extents;
  file_to_extents(cct, layout, offset, len, trunc_size, buffer_offset,
                  &lightweight_object_extents);

  // convert lightweight object extents to heavyweight version
  extents.reserve(lightweight_object_extents.size());
  for (auto& lightweight_object_extent : lightweight_object_extents) {
    auto& object_extent = extents.emplace_back(
      object_t(format_oid(object_format, lightweight_object_extent.object_no)),
      lightweight_object_extent.object_no,
      lightweight_object_extent.offset, lightweight_object_extent.length,
      lightweight_object_extent.truncate_size);

    object_extent.oloc = OSDMap::file_to_object_locator(*layout);
    object_extent.buffer_extents.reserve(
      lightweight_object_extent.buffer_extents.size());
    object_extent.buffer_extents.insert(
      object_extent.buffer_extents.end(),
      lightweight_object_extent.buffer_extents.begin(),
      lightweight_object_extent.buffer_extents.end());
  }
}

void Striper::file_to_extents(
  CephContext *cct, const char *object_format,
  const file_layout_t *layout,
  uint64_t offset, uint64_t len,
  uint64_t trunc_size,
  map<object_t,std::vector<ObjectExtent> >& object_extents,
  uint64_t buffer_offset)
{
  striper::LightweightObjectExtents lightweight_object_extents;
  file_to_extents(cct, layout, offset, len, trunc_size, buffer_offset,
                  &lightweight_object_extents);

  // convert lightweight object extents to heavyweight version
  for (auto& lightweight_object_extent : lightweight_object_extents) {
    auto oid = format_oid(object_format, lightweight_object_extent.object_no);
    auto& object_extent = object_extents[oid].emplace_back(
      oid, lightweight_object_extent.object_no,
      lightweight_object_extent.offset, lightweight_object_extent.length,
      lightweight_object_extent.truncate_size);

      object_extent.oloc = OSDMap::file_to_object_locator(*layout);
      object_extent.buffer_extents.reserve(
        lightweight_object_extent.buffer_extents.size());
      object_extent.buffer_extents.insert(
        object_extent.buffer_extents.end(),
        lightweight_object_extent.buffer_extents.begin(),
        lightweight_object_extent.buffer_extents.end());
  }
}

void Striper::file_to_extents(
    CephContext *cct, const file_layout_t *layout, uint64_t offset,
    uint64_t len, uint64_t trunc_size, uint64_t buffer_offset,
    striper::LightweightObjectExtents* object_extents) {
  ldout(cct, 10) << "file_to_extents " << offset << "~" << len << dendl;
  ceph_assert(len > 0);

  /*
   * we want only one extent per object!  this means that each extent
   * we read may map into different bits of the final read
   * buffer.. hence buffer_extents
   */

  __u32 object_size = layout->object_size;
  __u32 su = layout->stripe_unit;
  __u32 stripe_count = layout->stripe_count;
  ceph_assert(object_size >= su);
  if (stripe_count == 1) {
    ldout(cct, 20) << " sc is one, reset su to os" << dendl;
    su = object_size;
  }
  uint64_t stripes_per_object = object_size / su;
  ldout(cct, 20) << " su " << su << " sc " << stripe_count << " os "
		 << object_size << " stripes_per_object " << stripes_per_object
		 << dendl;

  uint64_t cur = offset;
  uint64_t left = len;
  while (left > 0) {
    // layout into objects
    uint64_t blockno = cur / su; // which block
    // which horizontal stripe (Y)
    uint64_t stripeno = blockno / stripe_count;
    // which object in the object set (X)
    uint64_t stripepos = blockno % stripe_count;
    // which object set
    uint64_t objectsetno = stripeno / stripes_per_object;
    // object id
    uint64_t objectno = objectsetno * stripe_count + stripepos;

    // map range into object
    uint64_t block_start = (stripeno % stripes_per_object) * su;
    uint64_t block_off = cur % su;
    uint64_t max = su - block_off;

    uint64_t x_offset = block_start + block_off;
    uint64_t x_len;
    if (left > max)
      x_len = max;
    else
      x_len = left;

    ldout(cct, 20) << " off " << cur << " blockno " << blockno << " stripeno "
		   << stripeno << " stripepos " << stripepos << " objectsetno "
		   << objectsetno << " objectno " << objectno
		   << " block_start " << block_start << " block_off "
		   << block_off << " " << x_offset << "~" << x_len
		   << dendl;

    striper::LightweightObjectExtent* ex = nullptr;
    auto it = std::upper_bound(object_extents->begin(), object_extents->end(),
                               objectno, OrderByObject());
    striper::LightweightObjectExtents::reverse_iterator rev_it(it);
    if (rev_it == object_extents->rend() ||
        rev_it->object_no != objectno ||
        rev_it->offset + rev_it->length != x_offset) {
      // expect up to "stripe-width - 1" vector shifts in the worst-case
      ex = &(*object_extents->emplace(
        it, objectno, x_offset, x_len,
        object_truncate_size(cct, layout, objectno, trunc_size)));
        ldout(cct, 20) << " added new " << *ex << dendl;
    } else {
      ex = &(*rev_it);
      ceph_assert(ex->offset + ex->length == x_offset);

      ldout(cct, 20) << " adding in to " << *ex << dendl;
      ex->length += x_len;
    }

    ex->buffer_extents.emplace_back(cur - offset + buffer_offset, x_len);

    ldout(cct, 15) << "file_to_extents  " << *ex << dendl;
    // ldout(cct, 0) << "map: ino " << ino << " oid " << ex.oid << " osd "
    //		  << ex.osd << " offset " << ex.offset << " len " << ex.len
    //		  << " ... left " << left << dendl;

    left -= x_len;
    cur += x_len;
  }
}

void Striper::extent_to_file(CephContext *cct, file_layout_t *layout,
			   uint64_t objectno, uint64_t off, uint64_t len,
			   std::vector<pair<uint64_t, uint64_t> >& extents)
{
  ldout(cct, 10) << "extent_to_file " << objectno << " " << off << "~"
		 << len << dendl;

  __u32 object_size = layout->object_size;
  __u32 su = layout->stripe_unit;
  __u32 stripe_count = layout->stripe_count;
  ceph_assert(object_size >= su);
  uint64_t stripes_per_object = object_size / su;
  ldout(cct, 20) << " stripes_per_object " << stripes_per_object << dendl;

  uint64_t off_in_block = off % su;

  extents.reserve(len / su + 1);

  while (len > 0) {
    uint64_t stripepos = objectno % stripe_count;
    uint64_t objectsetno = objectno / stripe_count;
    uint64_t stripeno = off / su + objectsetno * stripes_per_object;
    uint64_t blockno = stripeno * stripe_count + stripepos;
    uint64_t extent_off = blockno * su + off_in_block;
    uint64_t extent_len = std::min(len, su - off_in_block);
    extents.push_back(make_pair(extent_off, extent_len));

    ldout(cct, 20) << " object " << off << "~" << extent_len
		   << " -> file " << extent_off << "~" << extent_len
		   << dendl;

    off_in_block = 0;
    off += extent_len;
    len -= extent_len;
  }
}

uint64_t Striper::object_truncate_size(CephContext *cct,
				       const file_layout_t *layout,
				       uint64_t objectno, uint64_t trunc_size)
{
  uint64_t obj_trunc_size;
  if (trunc_size == 0 || trunc_size == (uint64_t)-1) {
    obj_trunc_size = trunc_size;
  } else {
    __u32 object_size = layout->object_size;
    __u32 su = layout->stripe_unit;
    __u32 stripe_count = layout->stripe_count;
    ceph_assert(object_size >= su);
    uint64_t stripes_per_object = object_size / su;

    uint64_t objectsetno = objectno / stripe_count;
    uint64_t trunc_objectsetno = trunc_size / object_size / stripe_count;
    if (objectsetno > trunc_objectsetno)
      obj_trunc_size = 0;
    else if (objectsetno < trunc_objectsetno)
      obj_trunc_size = object_size;
    else {
      uint64_t trunc_blockno = trunc_size / su;
      uint64_t trunc_stripeno = trunc_blockno / stripe_count;
      uint64_t trunc_stripepos = trunc_blockno % stripe_count;
      uint64_t trunc_objectno = trunc_objectsetno * stripe_count
	+ trunc_stripepos;
      if (objectno < trunc_objectno)
	obj_trunc_size = ((trunc_stripeno % stripes_per_object) + 1) * su;
      else if (objectno > trunc_objectno)
	obj_trunc_size = (trunc_stripeno % stripes_per_object) * su;
      else
	obj_trunc_size = (trunc_stripeno % stripes_per_object) * su
	  + (trunc_size % su);
    }
  }
  ldout(cct, 20) << "object_truncate_size " << objectno << " "
		 << trunc_size << "->" << obj_trunc_size << dendl;
  return obj_trunc_size;
}

uint64_t Striper::get_num_objects(const file_layout_t& layout,
				  uint64_t size)
{
  __u32 stripe_unit = layout.stripe_unit;
  __u32 stripe_count = layout.stripe_count;
  uint64_t period = layout.get_period();
  uint64_t num_periods = (size + period - 1) / period;
  uint64_t remainder_bytes = size % period;
  uint64_t remainder_objs = 0;
  if ((remainder_bytes > 0) && (remainder_bytes < (uint64_t)stripe_count
				* stripe_unit))
    remainder_objs = stripe_count - ((remainder_bytes + stripe_unit - 1)
				     / stripe_unit);
  return num_periods * stripe_count - remainder_objs;
}

uint64_t Striper::get_file_offset(CephContext *cct,
        const file_layout_t *layout, uint64_t objectno, uint64_t off) {
  ldout(cct, 10) << "get_file_offset " << objectno << " " << off  << dendl;

  __u32 object_size = layout->object_size;
  __u32 su = layout->stripe_unit;
  __u32 stripe_count = layout->stripe_count;
  ceph_assert(object_size >= su);
  uint64_t stripes_per_object = object_size / su;
  ldout(cct, 20) << " stripes_per_object " << stripes_per_object << dendl;

  uint64_t off_in_block = off % su;

  uint64_t stripepos = objectno % stripe_count;
  uint64_t objectsetno = objectno / stripe_count;
  uint64_t stripeno = off / su + objectsetno * stripes_per_object;
  uint64_t blockno = stripeno * stripe_count + stripepos;
  return blockno * su + off_in_block;
}

// StripedReadResult

void Striper::StripedReadResult::add_partial_result(
  CephContext *cct, bufferlist& bl,
  const std::vector<pair<uint64_t,uint64_t> >& buffer_extents)
{
  ldout(cct, 10) << "add_partial_result(" << this << ") " << bl.length()
		 << " to " << buffer_extents << dendl;
  for (auto p = buffer_extents.cbegin(); p != buffer_extents.cend(); ++p) {
    pair<bufferlist, uint64_t>& r = partial[p->first];
    size_t actual = std::min<uint64_t>(bl.length(), p->second);
    bl.splice(0, actual, &r.first);
    r.second = p->second;
    total_intended_len += r.second;
  }
}

void Striper::StripedReadResult::add_partial_result(
  CephContext *cct, bufferlist&& bl,
  const striper::LightweightBufferExtents& buffer_extents)
{
  ldout(cct, 10) << "add_partial_result(" << this << ") " << bl.length()
		 << " to " << buffer_extents << dendl;
  for (auto& be : buffer_extents) {
    auto& r = partial[be.first];
    size_t actual = std::min<uint64_t>(bl.length(), be.second);
    if (buffer_extents.size() == 1) {
      r.first = std::move(bl);
    } else {
      bl.splice(0, actual, &r.first);
    }
    r.second = be.second;
    total_intended_len += r.second;
  }
}

void Striper::StripedReadResult::add_partial_sparse_result(
  CephContext *cct, bufferlist& bl, const map<uint64_t, uint64_t>& bl_map,
  uint64_t bl_off, const std::vector<pair<uint64_t,uint64_t> >& buffer_extents)
{
  ldout(cct, 10) << "add_partial_sparse_result(" << this << ") " << bl.length()
		 << " covering " << bl_map << " (offset " << bl_off << ")"
		 << " to " << buffer_extents << dendl;

  if (bl_map.empty()) {
    add_partial_result(cct, bl, buffer_extents);
    return;
  }

  auto s = bl_map.cbegin();
  for (auto& be : buffer_extents) {
    ::add_partial_sparse_result(cct, &partial, &total_intended_len, bl, &s,
                                bl_map.end(), &bl_off, be.first, be.second);
  }
}

void Striper::StripedReadResult::add_partial_sparse_result(
    CephContext *cct, ceph::buffer::list&& bl,
    const std::vector<std::pair<uint64_t, uint64_t>>& bl_map, uint64_t bl_off,
    const striper::LightweightBufferExtents& buffer_extents) {
  ldout(cct, 10) << "add_partial_sparse_result(" << this << ") " << bl.length()
		 << " covering " << bl_map << " (offset " << bl_off << ")"
		 << " to " << buffer_extents << dendl;

  if (bl_map.empty()) {
    add_partial_result(cct, std::move(bl), buffer_extents);
    return;
  }

  auto s = bl_map.cbegin();
  for (auto& be : buffer_extents) {
    ::add_partial_sparse_result(cct, &partial, &total_intended_len, bl, &s,
                                bl_map.cend(), &bl_off, be.first, be.second);
  }
}

void Striper::StripedReadResult::assemble_result(CephContext *cct,
						 bufferlist& bl,
						 bool zero_tail)
{
  ldout(cct, 10) << "assemble_result(" << this << ") zero_tail=" << zero_tail
		 << dendl;
  size_t zeros = 0;  // zeros preceding current position
  for (auto& p : partial) {
    size_t got = p.second.first.length();
    size_t expect = p.second.second;
    if (got) {
      if (zeros) {
	bl.append_zero(zeros);
	zeros = 0;
      }
      bl.claim_append(p.second.first);
    }
    zeros += expect - got;
  }
  if (zero_tail && zeros) {
    bl.append_zero(zeros);
  }
  partial.clear();
}

void Striper::StripedReadResult::assemble_result(CephContext *cct, char *buffer, size_t length)
{
  ceph_assert(length == total_intended_len);

  map<uint64_t,pair<bufferlist,uint64_t> >::reverse_iterator p = partial.rbegin();
  if (p == partial.rend())
    return;

  ceph_assert(buffer);

  uint64_t curr = length;
  uint64_t end = p->first + p->second.second;
  while (p != partial.rend()) {
    // sanity check
    ldout(cct, 20) << "assemble_result(" << this << ") " << p->first << "~" << p->second.second
		   << " " << p->second.first.length() << " bytes"
		   << dendl;
    ceph_assert(p->first == end - p->second.second);
    end = p->first;

    size_t len = p->second.first.length();
    ceph_assert(curr >= p->second.second);
    curr -= p->second.second;
    if (len < p->second.second) {
      if (len)
	p->second.first.begin().copy(len, buffer + curr);
      // FIPS zeroization audit 20191117: this memset is not security related.
      memset(buffer + curr + len, 0, p->second.second - len);
    } else {
      p->second.first.begin().copy(len, buffer + curr);
    }
    ++p;
  }
  partial.clear();
  ceph_assert(curr == 0);
}

uint64_t Striper::StripedReadResult::assemble_result(
    CephContext *cct, std::map<uint64_t, uint64_t> *extent_map,
    bufferlist *bl)
{
  ldout(cct, 10) << "assemble_result(" << this << ")" << dendl;
  for (auto& p : partial) {
    uint64_t off = p.first;
    uint64_t len = p.second.first.length();
    if (len > 0) {
      (*extent_map)[off] = len;
      bl->claim_append(p.second.first);
    }
  }
  partial.clear();
  return total_intended_len;
}
