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construct/ircd/m_state.cc

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C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
// Linkages for the state::node json::tuple property strings. This is similar
// to m::name (name.h / name.cc) but since this is very specific to m::state
// we keep it here.
constexpr const char *const
ircd::m::state::name::key;
constexpr const char *const
ircd::m::state::name::val;
constexpr const char *const
ircd::m::state::name::child;
constexpr const char *const
ircd::m::state::name::count;
/// Convenience to make a key and then get a value
void
ircd::m::state::get(const string_view &root,
const string_view &type,
const string_view &state_key,
const val_closure &closure)
{
if(!get(std::nothrow, root, type, state_key, closure))
throw m::NOT_FOUND
{
"type='%s' state_key='%s' not found in tree %s",
type,
state_key,
root
};
}
/// Convenience to make a key and then get a value (doesn't throw NOT_FOUND)
bool
ircd::m::state::get(std::nothrow_t,
const string_view &root,
const string_view &type,
const string_view &state_key,
const val_closure &closure)
{
char key[KEY_MAX_SZ];
return get(std::nothrow, root, make_key(key, type, state_key), closure);
}
/// throws m::NOT_FOUND if the exact key and its value does not exist.
void
ircd::m::state::get(const string_view &root,
const json::array &key,
const val_closure &closure)
{
if(!get(std::nothrow, root, key, closure))
throw m::NOT_FOUND
{
"%s not found in tree %s",
string_view{key},
root
};
}
/// Recursive query to find the leaf value for the given key, starting from
/// the given root node ID. Value can be viewed in the closure. Returns false
/// if the exact key and its value does not exist in the tree; no node ID's
/// are ever returned here.
bool
ircd::m::state::get(std::nothrow_t,
const string_view &root,
const json::array &key,
const val_closure &closure)
{
bool ret{false};
char nextbuf[ID_MAX_SZ];
string_view nextid{root};
const auto node_closure{[&ret, &nextbuf, &nextid, &key, &closure]
(const node &node)
{
auto pos(node.find(key));
if(pos < node.keys() && node.key(pos) == key)
{
ret = true;
nextid = {};
closure(node.val(pos));
return;
}
const auto c(node.childs());
if(c && pos >= c)
pos = c - 1;
if(node.has_child(pos))
nextid = { nextbuf, strlcpy(nextbuf, node.child(pos)) };
else
nextid = {};
}};
while(nextid)
if(!get_node(std::nothrow, nextid, node_closure))
return false;
return ret;
}
size_t
ircd::m::state::accumulate(const string_view &root,
const iter_bool_closure &closure)
{
size_t ret{0};
for_each(root, [&ret, &closure]
(const json::array &key, const string_view &val)
{
ret += closure(key, val);
});
return ret;
}
void
ircd::m::state::for_each(const string_view &root,
const iter_closure &closure)
{
for_each(root, iter_bool_closure{[&closure]
(const json::array &key, const string_view &val)
{
closure(key, val);
return true;
}});
}
bool
ircd::m::state::for_each(const string_view &root,
const iter_bool_closure &closure)
{
return !dfs(root, [&closure]
(const json::array &key, const string_view &val, const uint &, const uint &)
{
return !closure(key, val);
});
}
void
ircd::m::state::for_each(const string_view &root,
const string_view &type,
const iter_closure &closure)
{
for_each(root, type, iter_bool_closure{[&closure]
(const json::array &key, const string_view &val)
{
closure(key, val);
return true;
}});
}
bool
ircd::m::state::for_each(const string_view &root,
const string_view &type,
const iter_bool_closure &closure)
{
char buf[KEY_MAX_SZ];
const json::array key
{
make_key(buf, type)
};
return !dfs(root, key, [&closure]
(const json::array &key, const string_view &val, const uint &, const uint &)
{
return !closure(key, val);
});
}
bool
ircd::m::state::for_each(const string_view &root,
const string_view &type,
const string_view &state_key_lb,
const iter_bool_closure &closure)
{
char buf[KEY_MAX_SZ];
const json::array key
{
make_key(buf, type, state_key_lb)
};
return !dfs(root, key, [&closure]
(const json::array &key, const string_view &val, const uint &, const uint &)
{
return !closure(key, val);
});
}
namespace ircd::m::state
{
size_t _count_recurse(const node &, const json::array &key, const json::array &dom);
size_t _count(const string_view &root, const json::array &key);
}
size_t
ircd::m::state::count(const string_view &root)
{
return 0;
}
size_t
ircd::m::state::count(const string_view &root,
const string_view &type)
{
if(!type)
return count(root);
char buf[KEY_MAX_SZ];
const json::array key
{
make_key(buf, type)
};
return _count(root, key);
}
size_t
ircd::m::state::_count(const string_view &root,
const json::array &key)
{
size_t ret{0};
get_node(std::nothrow, root, [&key, &ret]
(const auto &node)
{
ret += _count_recurse(node, key, json::array{});
});
return ret;
}
size_t
ircd::m::state::_count_recurse(const node &node,
const json::array &key,
const json::array &dom)
{
const node::rep rep{node};
bool under{!empty(dom)};
for(uint pos(0); under && pos < rep.kn; ++pos)
if(!prefix_eq(dom, rep.keys[pos]))
under = false;
if(under)
return rep.totals();
size_t ret{0};
const auto kpos{rep.find(key)};
for(uint pos(kpos); pos < rep.kn || pos < rep.cn; ++pos)
{
if(!empty(rep.chld[pos]))
get_node(std::nothrow, rep.chld[pos], [&key, &ret, &rep, &pos]
(const auto &node)
{
ret += _count_recurse(node, key, rep.keys[pos]);
});
if(pos < rep.kn)
{
if(prefix_eq(key, rep.keys[pos]))
++ret;
else
break;
}
}
return ret;
}
namespace ircd::m::state
{
bool _dfs_recurse(const search_closure &, const node &, const json::array &key, int &);
}
bool
ircd::m::state::dfs(const string_view &root,
const search_closure &closure)
{
return dfs(root, json::array{}, closure);
}
bool
ircd::m::state::dfs(const string_view &root,
const json::array &key,
const search_closure &closure)
{
bool ret{false};
get_node(std::nothrow, root, [&closure, &key, &ret]
(const auto &node)
{
int depth(-1);
ret = _dfs_recurse(closure, node, key, depth);
});
return ret;
}
bool
ircd::m::state::_dfs_recurse(const search_closure &closure,
const node &node,
const json::array &key,
int &depth)
{
const scope_count down
{
depth
};
const node::rep rep{node};
const auto kpos{rep.find(key)};
for(uint pos(kpos); pos < rep.kn || pos < rep.cn; ++pos)
{
if(!empty(rep.chld[pos]))
{
bool ret{false};
get_node(std::nothrow, rep.chld[pos], [&closure, &key, &depth, &ret]
(const auto &node)
{
ret = _dfs_recurse(closure, node, key, depth);
});
if(ret)
return true;
}
if(rep.kn <= pos)
continue;
if(!empty(key) && !prefix_eq(key, rep.keys[pos]))
break;
if(closure(rep.keys[pos], rep.vals[pos], depth, pos))
return true;
}
return false;
}
// Internal operations
namespace ircd::m::state
{
static mutable_buffer _getbuffer(const uint8_t &height);
static string_view _remove(int8_t &height, db::txn &, const json::array &key, const node &node, const mutable_buffer &idbuf, node::rep &push);
static string_view _insert_overwrite(db::txn &, const json::array &key, const string_view &val, const mutable_buffer &idbuf, node::rep &, const size_t &pos);
static string_view _insert_leaf_nonfull(db::txn &, const json::array &key, const string_view &val, const mutable_buffer &idbuf, node::rep &, const size_t &pos);
static json::object _insert_leaf_full(const int8_t &height, db::txn &, const json::array &key, const string_view &val, node::rep &, const size_t &pos, node::rep &push);
static string_view _insert_branch_nonfull(db::txn &, const mutable_buffer &idbuf, node::rep &, const size_t &pos, node::rep &pushed);
static json::object _insert_branch_full(const int8_t &height, db::txn &, node::rep &, const size_t &pos, node::rep &push, const node::rep &pushed);
static string_view _insert(int8_t &height, db::txn &, const json::array &key, const string_view &val, const node &node, const mutable_buffer &idbuf, node::rep &push);
static string_view _create(db::txn &, const mutable_buffer &root, const string_view &type, const string_view &state_key, const string_view &val);
}
/// State update from an event. Leaves the root node ID in the root buffer;
/// returns view.
///
ircd::m::state::id
ircd::m::state::insert(db::txn &txn,
const mutable_buffer &rootout,
const string_view &rootin,
const event &event)
{
const auto &type{at<"type"_>(event)};
const auto &state_key{at<"state_key"_>(event)};
const auto &event_id{at<"event_id"_>(event)};
assert(defined(state_key));
if(empty(rootin))
return _create(txn, rootout, type, state_key, event_id);
return insert(txn, rootout, rootin, type, state_key, event_id);
}
ircd::m::state::id
ircd::m::state::_create(db::txn &txn,
const mutable_buffer &root,
const string_view &type,
const string_view &state_key,
const string_view &val)
{
// Because this is a new tree and nothing is read from the DB, all
// writes here are just copies into the txn and these buffers can
// remain off-stack.
const critical_assertion ca;
thread_local char key[KEY_MAX_SZ];
thread_local char node[NODE_MAX_SZ];
node::rep rep;
rep.keys[0] = make_key(key, type, state_key);
rep.kn = 1;
rep.vals[0] = val;
rep.vn = 1;
rep.chld[0] = string_view{};
rep.cn = 1;
rep.cnts[0] = 0;
rep.nn = 1;
return set_node(txn, root, rep.write(node));
}
/// State update for room_id inserting (type,state_key) = event_id into the
/// tree. Leaves the root node ID in the root buffer; returns view.
ircd::m::state::id
ircd::m::state::insert(db::txn &txn,
const mutable_buffer &rootout,
const string_view &rootin,
const string_view &type,
const string_view &state_key,
const m::id::event &event_id)
{
// The insertion process reads from the DB and will yield this ircd::ctx
// so the key buffer must stay on this stack.
char key[KEY_MAX_SZ];
return insert(txn, rootout, rootin, make_key(key, type, state_key), event_id);
}
ircd::m::state::id
ircd::m::state::insert(db::txn &txn,
const mutable_buffer &rootout,
const string_view &rootin,
const json::array &key,
const m::id::event &event_id)
{
node::rep push;
int8_t height{0};
string_view root{rootin};
get_node(root, [&](const node &node)
{
root = _insert(height, txn, key, event_id, node, rootout, push);
});
if(push.kn)
root = push.write(txn, rootout);
return root;
}
ircd::m::state::id
ircd::m::state::_insert(int8_t &height,
db::txn &txn,
const json::array &key,
const string_view &val,
const node &node,
const mutable_buffer &idbuf,
node::rep &push)
{
// Recursion metrics
const scope_count down{height};
if(unlikely(height >= MAX_HEIGHT))
throw panic
{
"recursion limit exceeded"
};
// This function assumes that any node argument is a previously "existing"
// node which means it contains at least one key/value.
assert(node.keys() > 0);
assert(node.keys() == node.vals());
node::rep rep{node};
const auto pos{node.find(key)};
if(keycmp(node.key(pos), key) == 0)
return _insert_overwrite(txn, key, val, idbuf, rep, pos);
if(node.childs() == 0 && rep.full())
return _insert_leaf_full(height, txn, key, val, rep, pos, push);
if(node.childs() == 0 && !rep.full())
return _insert_leaf_nonfull(txn, key, val, idbuf, rep, pos);
if(empty(node.child(pos)))
return _insert_leaf_nonfull(txn, key, val, idbuf, rep, pos);
// These collect data from the next level.
node::rep pushed;
string_view child;
// Recurse
get_node(node.child(pos), [&](const auto &node)
{
child = _insert(height, txn, key, val, node, idbuf, pushed);
});
// Child was pushed but that will stop here.
if(pushed.kn && !rep.full())
return _insert_branch_nonfull(txn, idbuf, rep, pos, pushed);
// Most complex branch
if(pushed.kn && rep.full())
return _insert_branch_full(height, txn, rep, pos, push, pushed);
// Indicates no push, and the child value is just an ID of a node.
rep.chld[pos] = child;
rep.cnts[pos]++;
return rep.write(txn, idbuf);
}
ircd::json::object
ircd::m::state::_insert_branch_full(const int8_t &height,
db::txn &txn,
node::rep &rep,
const size_t &pos,
node::rep &push,
const node::rep &pushed)
{
rep.shr(pos);
rep.keys[pos] = pushed.keys[0];
++rep.kn;
rep.vals[pos] = pushed.vals[0];
++rep.vn;
rep.chld[pos] = pushed.chld[0];
rep.chld[pos + 1] = pushed.chld[1];
++rep.cn;
rep.cnts[pos] = pushed.cnts[0];
rep.cnts[pos + 1] = pushed.cnts[1];
++rep.nn;
size_t i(0);
node::rep left;
for(; i < rep.kn / 2; ++i)
{
left.keys[left.kn++] = rep.keys[i];
left.vals[left.vn++] = rep.vals[i];
left.chld[left.cn++] = rep.chld[i];
left.cnts[left.nn++] = rep.cnts[i];
}
left.chld[left.cn++] = rep.chld[i];
left.cnts[left.nn++] = rep.cnts[i];
push.keys[push.kn++] = rep.keys[i];
push.vals[push.vn++] = rep.vals[i];
node::rep right;
for(++i; i < rep.kn; ++i)
{
right.keys[right.kn++] = rep.keys[i];
right.vals[right.vn++] = rep.vals[i];
right.chld[right.cn++] = rep.chld[i];
right.cnts[right.nn++] = rep.cnts[i];
}
right.chld[right.cn++] = rep.chld[i];
right.cnts[right.nn++] = rep.cnts[i];
thread_local char lc[ID_MAX_SZ], rc[ID_MAX_SZ];
push.chld[push.cn++] = left.write(txn, lc);
push.chld[push.cn++] = right.write(txn, rc);
push.cnts[push.nn++] = left.totals();
push.cnts[push.nn++] = right.totals();
const auto ret
{
push.write(_getbuffer(height))
};
// Courtesy reassignment of all the references in `push` after rewrite.
push = state::node{ret};
return ret;
}
ircd::json::object
ircd::m::state::_insert_leaf_full(const int8_t &height,
db::txn &txn,
const json::array &key,
const string_view &val,
node::rep &rep,
const size_t &pos,
node::rep &push)
{
rep.shr(pos);
rep.keys[pos] = key;
++rep.kn;
rep.vals[pos] = val;
++rep.vn;
size_t i(0);
node::rep left;
for(; i < rep.kn / 2; ++i)
{
left.keys[left.kn++] = rep.keys[i];
left.vals[left.vn++] = rep.vals[i];
left.chld[left.cn++] = string_view{};
left.cnts[left.nn++] = 0;
}
push.keys[push.kn++] = rep.keys[i];
push.vals[push.vn++] = rep.vals[i];
node::rep right;
for(++i; i < rep.kn; ++i)
{
right.keys[right.kn++] = rep.keys[i];
right.vals[right.vn++] = rep.vals[i];
right.chld[right.cn++] = string_view{};
right.cnts[right.nn++] = 0;
}
thread_local char lc[ID_MAX_SZ], rc[ID_MAX_SZ];
push.chld[push.cn++] = left.write(txn, lc);
push.chld[push.cn++] = right.write(txn, rc);
push.cnts[push.nn++] = left.totals();
push.cnts[push.nn++] = right.totals();
const auto ret
{
push.write(_getbuffer(height))
};
// Courtesy reassignment of all the references in `push` after rewrite.
push = state::node{ret};
return ret;
}
ircd::m::state::id
ircd::m::state::_insert_branch_nonfull(db::txn &txn,
const mutable_buffer &idbuf,
node::rep &rep,
const size_t &pos,
node::rep &pushed)
{
rep.shr(pos);
rep.keys[pos] = pushed.keys[0];
++rep.kn;
rep.vals[pos] = pushed.vals[0];
++rep.vn;
rep.chld[pos] = pushed.chld[0];
rep.chld[pos + 1] = pushed.chld[1];
++rep.cn;
rep.cnts[pos] = pushed.cnts[0];
rep.cnts[pos + 1] = pushed.cnts[1];
++rep.nn;
return rep.write(txn, idbuf);
}
ircd::m::state::id
ircd::m::state::_insert_leaf_nonfull(db::txn &txn,
const json::array &key,
const string_view &val,
const mutable_buffer &idbuf,
node::rep &rep,
const size_t &pos)
{
rep.shr(pos);
rep.keys[pos] = key;
++rep.kn;
rep.vals[pos] = val;
++rep.vn;
rep.chld[pos] = string_view{};
++rep.cn;
rep.cnts[pos] = 0;
++rep.nn;
return rep.write(txn, idbuf);
}
ircd::m::state::id
ircd::m::state::_insert_overwrite(db::txn &txn,
const json::array &key,
const string_view &val,
const mutable_buffer &idbuf,
node::rep &rep,
const size_t &pos)
{
rep.keys[pos] = key;
rep.vals[pos] = val;
return rep.write(txn, idbuf);
}
ircd::m::state::id
ircd::m::state::remove(db::txn &txn,
const mutable_buffer &rootout,
const string_view &rootin,
const event &event)
{
const auto &type{at<"type"_>(event)};
const auto &state_key{at<"state_key"_>(event)};
assert(!empty(rootin));
return remove(txn, rootout, rootin, type, state_key);
}
/// State update for room_id inserting (type,state_key) = event_id into the
/// tree. Leaves the root node ID in the root buffer; returns view.
ircd::m::state::id
ircd::m::state::remove(db::txn &txn,
const mutable_buffer &rootout,
const string_view &rootin,
const string_view &type,
const string_view &state_key)
{
// The removal process reads from the DB and will yield this ircd::ctx
// so the key buffer must stay on this stack.
char key[KEY_MAX_SZ];
return remove(txn, rootout, rootin, make_key(key, type, state_key));
}
ircd::m::state::id
ircd::m::state::remove(db::txn &txn,
const mutable_buffer &rootout,
const string_view &rootin,
const json::array &key)
{
node::rep push;
int8_t height{0};
string_view root{rootin};
get_node(root, [&](const node &node)
{
root = _remove(height, txn, key, node, rootout, push);
});
if(push.kn)
root = push.write(txn, rootout);
return root;
}
ircd::m::state::id
ircd::m::state::_remove(int8_t &height,
db::txn &txn,
const json::array &key,
const node &node,
const mutable_buffer &idbuf,
node::rep &push)
{
const scope_count down{height};
if(unlikely(height >= MAX_HEIGHT))
throw panic
{
"recursion limit exceeded"
};
node::rep rep{node};
const auto pos{node.find(key)};
if(keycmp(node.key(pos), key) == 0)
{
return {};
}
// These collect data from the next level.
node::rep pushed;
string_view child;
// Recurse
get_node(node.child(pos), [&](const auto &node)
{
child = _remove(height, txn, key, node, idbuf, pushed);
});
return {};
}
/// This function returns a thread_local buffer intended for writing temporary
/// nodes which may be "pushed" down the tree during the btree insertion
/// process. This is an alternative to allocating such space in each stack
/// frame when only one or two are ever used at a time -- but because more than
/// one may be used at a time during complex rebalances we have the user pass
/// their current recursion depth which is used to partition the buffer so they
/// don't overwrite their own data.
ircd::mutable_buffer
ircd::m::state::_getbuffer(const uint8_t &height)
{
static const size_t buffers{2};
using buffer_type = std::array<char, NODE_MAX_SZ>;
thread_local std::array<buffer_type, buffers> buffer;
return buffer.at(height % buffer.size());
}
/// View a node by ID. This makes a DB query and may yield ircd::ctx.
void
ircd::m::state::get_node(const string_view &node_id,
const node_closure &closure)
{
if(!get_node(std::nothrow, node_id, closure))
throw m::NOT_FOUND
{
"node_id %s not found",
string_view{node_id}
};
}
/// View a node by ID. This makes a DB query and may yield ircd::ctx.
bool
ircd::m::state::get_node(const std::nothrow_t,
const string_view &node_id,
const node_closure &closure)
{
assert(bool(dbs::state_node));
auto &column{dbs::state_node};
return column(node_id, std::nothrow, closure);
}
/// Writes a node to the db::txn and returns the id of this node (a hash) into
/// the buffer.
ircd::m::state::id
ircd::m::state::set_node(db::txn &iov,
const mutable_buffer &hashbuf,
const json::object &node)
{
const sha256::buf hash
{
sha256{node}
};
const auto hashb64
{
b64encode_unpadded(hashbuf, hash)
};
db::txn::append
{
iov, dbs::state_node,
{
db::op::SET,
hashb64, // key
node, // val
}
};
return hashb64;
}
/// Convenience inverse of make_key.
ircd::string_view
ircd::m::state::unmake_key(const mutable_buffer &out,
const json::array &key)
{
window_buffer wb{out};
for(const auto &part : key)
wb([&part](const mutable_buffer &buf)
{
assert(json::type(part) == json::STRING);
return copy(buf, unquote(part));
});
return wb.completed();
}
ircd::json::array
ircd::m::state::make_key(const mutable_buffer &out,
const string_view &type)
{
return make_key(out, type, string_view{});
}
/// Creates a key array from the most common key pattern of a matrix
/// room (type,state_key).
ircd::json::array
ircd::m::state::make_key(const mutable_buffer &out,
const string_view &type,
const string_view &state_key)
{
const json::value key_parts[]
{
type, state_key
};
assert(defined(type));
const size_t &part_count
{
defined(state_key)? 2UL : 1UL
};
const json::value key
{
key_parts, part_count
};
return { data(out), json::print(out, key) };
}
bool
ircd::m::state::prefix_eq(const json::array &a,
const json::array &b)
{
ushort i(0);
auto ait(begin(a));
auto bit(begin(b));
for(; ait != end(a) && bit != end(b) && i < 2; ++ait, ++bit)
{
assert(surrounds(*ait, '"'));
assert(surrounds(*bit, '"'));
if(*ait == *bit)
{
if(i)
return false;
}
else ++i;
}
return ait != end(a) || bit != end(b)? i == 0 : i < 2;
}
/// Compares two keys. Keys are arrays of strings which become safely
/// concatenated for a linear lexical comparison. Returns -1 if a less
/// than b; 0 if equal; 1 if a greater than b.
int
ircd::m::state::keycmp(const json::array &a,
const json::array &b)
{
auto ait(begin(a));
auto bit(begin(b));
for(; ait != end(a) && bit != end(b); ++ait, ++bit)
{
assert(surrounds(*ait, '"'));
assert(surrounds(*bit, '"'));
if(*ait < *bit)
return -1;
if(*bit < *ait)
return 1;
}
assert(ait == end(a) || bit == end(b));
return ait == end(a) && bit != end(b)? -1:
ait == end(a) && bit == end(b)? 0:
1;
}
//
// rep
//
ircd::m::state::node::rep::rep(const node &node)
:kn{node.keys(keys.data(), keys.size())}
,vn{node.vals(vals.data(), vals.size())}
,cn{node.childs(chld.data(), chld.size())}
,nn{node.counts(cnts.data(), cnts.size())}
{
assert(cn == nn);
}
ircd::m::state::id
ircd::m::state::node::rep::write(db::txn &txn,
const mutable_buffer &idbuf)
{
thread_local char buf[NODE_MAX_SZ];
return set_node(txn, idbuf, write(buf));
}
ircd::json::object
ircd::m::state::node::rep::write(const mutable_buffer &out)
{
assert(kn == vn);
assert(cn == nn);
assert(cn <= kn + 1);
assert(!childs() || childs() > kn);
assert(!duplicates());
assert(kn > 0 && vn > 0);
assert(kn <= NODE_MAX_KEY);
assert(vn <= NODE_MAX_VAL);
assert(cn <= NODE_MAX_DEG);
std::array<json::value, NODE_MAX_KEY> keys;
{
for(size_t i(0); i < kn; ++i)
keys[i] = this->keys[i];
}
std::array<json::value, NODE_MAX_VAL> vals;
{
for(size_t i(0); i < vn; ++i)
vals[i] = this->vals[i];
};
std::array<json::value, NODE_MAX_DEG> chld;
{
for(size_t i(0); i < cn; ++i)
chld[i] = this->chld[i];
};
std::array<json::value, NODE_MAX_DEG> cnts;
{
for(size_t i(0); i < nn; ++i)
cnts[i] = json::value{long(this->cnts[i])};
};
json::iov iov;
const json::iov::push push[]
{
{ iov, { name::key, { keys.data(), kn } } },
{ iov, { name::val, { vals.data(), vn } } },
{ iov, { name::child, { chld.data(), cn } } },
{ iov, { name::count, { cnts.data(), nn } } },
};
return { data(out), json::print(out, iov) };
}
/// Shift right.
void
ircd::m::state::node::rep::shr(const size_t &pos)
{
std::copy_backward(begin(keys) + pos, begin(keys) + kn, begin(keys) + kn + 1);
std::copy_backward(begin(vals) + pos, begin(vals) + vn, begin(vals) + vn + 1);
std::copy_backward(begin(chld) + pos, begin(chld) + cn, begin(chld) + cn + 1);
std::copy_backward(begin(cnts) + pos, begin(cnts) + nn, begin(cnts) + nn + 1);
}
/// Shift left.
void
ircd::m::state::node::rep::shl(const size_t &pos)
{
std::copy(begin(keys) + pos + 1, begin(keys) + kn, begin(keys) + std::max(ssize_t(kn) - 1, 0L));
std::copy(begin(vals) + pos + 1, begin(vals) + vn, begin(vals) + std::max(ssize_t(vn) - 1, 0L));
std::copy(begin(chld) + pos + 1, begin(chld) + cn, begin(chld) + std::max(ssize_t(cn) - 1, 0L));
std::copy(begin(cnts) + pos + 1, begin(cnts) + nn, begin(cnts) + std::max(ssize_t(nn) - 1, 0L));
}
size_t
ircd::m::state::node::rep::find(const json::array &parts)
const
{
size_t i{0};
for(; i < kn; ++i)
if(keycmp(parts, keys[i]) <= 0)
return i;
return i;
}
size_t
ircd::m::state::node::rep::totals()
const
{
return kn + counts();
}
size_t
ircd::m::state::node::rep::counts()
const
{
size_t ret(0);
for(size_t i(0); i < nn; ++i)
ret += cnts[i];
return ret;
}
size_t
ircd::m::state::node::rep::childs()
const
{
size_t ret(0);
for(size_t i(0); i < cn; ++i)
if(!empty(unquote(chld[i])))
++ret;
return ret;
}
bool
ircd::m::state::node::rep::duplicates()
const
{
for(size_t i(0); i < kn; ++i)
for(size_t j(0); j < kn; ++j)
if(j != i && keys[i] == keys[j])
return true;
for(size_t i(0); i < cn; ++i)
if(!empty(unquote(chld[i])))
for(size_t j(0); j < cn; ++j)
if(j != i && chld[i] == chld[j])
return true;
return false;
}
bool
ircd::m::state::node::rep::overfull()
const
{
assert(kn == vn);
return kn > NODE_MAX_KEY;
}
bool
ircd::m::state::node::rep::last()
const
{
assert(kn == vn);
return kn == 1;
}
bool
ircd::m::state::node::rep::full()
const
{
assert(kn == vn);
return kn >= NODE_MAX_KEY;
}
//
// node
//
// Count values that actually lead to other nodes
bool
ircd::m::state::node::has_child(const size_t &pos)
const
{
return !empty(child(pos));
}
// Count values that actually lead to other nodes
bool
ircd::m::state::node::has_key(const json::array &key)
const
{
const auto pos(find(key));
if(pos >= keys())
return false;
return keycmp(this->key(pos), key) == 0;
}
/// Find position for a val in node. Uses the keycmp(). If there is one
/// key in node, and the argument compares less than or equal to the key,
/// 0 is returned, otherwise 1 is returned. If there are two keys in node
/// and argument compares less than both, 0 is returned; equal to key[0],
/// 0 is returned; greater than key[0] and less than or equal to key[1],
/// 1 is returned; greater than both: 2 is returned. Note that there can
/// be one more childs() than keys() in a node (this is usually a "full
/// node") but there might not be, and the returned pos might be out of
/// range.
size_t
ircd::m::state::node::find(const json::array &parts)
const
{
size_t ret{0};
for(const json::array key : json::get<name::key>(*this))
if(keycmp(parts, key) <= 0)
return ret;
else
++ret;
return ret;
}
size_t
ircd::m::state::node::counts(size_t *const &out,
const size_t &max)
const
{
size_t i(0);
for(const string_view &c : json::get<name::count>(*this))
if(likely(i < max))
out[i++] = lex_cast<size_t>(c);
return i;
}
size_t
ircd::m::state::node::childs(state::id *const &out,
const size_t &max)
const
{
size_t i(0);
for(const string_view &c : json::get<name::child>(*this))
if(likely(i < max))
out[i++] = unquote(c);
return i;
}
size_t
ircd::m::state::node::vals(string_view *const &out,
const size_t &max)
const
{
size_t i(0);
for(const string_view &v : json::get<name::val>(*this))
if(likely(i < max))
out[i++] = unquote(v);
return i;
}
size_t
ircd::m::state::node::keys(json::array *const &out,
const size_t &max)
const
{
size_t i(0);
for(const json::array &k : json::get<name::key>(*this))
if(likely(i < max))
out[i++] = k;
return i;
}
size_t
ircd::m::state::node::count(const size_t &pos)
const
{
const json::array &counts
{
json::get<name::count>(*this, json::empty_array)
};
return counts.at<size_t>(pos);
}
ircd::m::state::id
ircd::m::state::node::child(const size_t &pos)
const
{
const json::array &children
{
json::get<name::child>(*this, json::empty_array)
};
return unquote(children[pos]);
}
// Get value at position pos (throws out_of_range)
ircd::string_view
ircd::m::state::node::val(const size_t &pos)
const
{
const json::array &values
{
json::get<name::val>(*this, json::empty_array)
};
return unquote(values[pos]);
}
// Get key at position pos (throws out_of_range)
ircd::json::array
ircd::m::state::node::key(const size_t &pos)
const
{
const json::array &keys
{
json::get<name::key>(*this, json::empty_array)
};
return keys[pos];
}
// Count counts in node
size_t
ircd::m::state::node::totals()
const
{
return keys() + counts();
}
// Count counts in node
size_t
ircd::m::state::node::counts()
const
{
size_t ret(0);
for(const auto &c : json::get<name::count>(*this))
ret += lex_cast<size_t>(c);
return ret;
}
// Count children in node
size_t
ircd::m::state::node::childs()
const
{
size_t ret(0);
for(const auto &c : json::get<name::child>(*this))
ret += !empty(c) && c != json::empty_string;
return ret;
}
// Count values in node
size_t
ircd::m::state::node::vals()
const
{
return json::get<name::val>(*this).count();
}
/// Count keys in node
size_t
ircd::m::state::node::keys()
const
{
return json::get<name::key>(*this).count();
}