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Make AreaStore IDs persistent (#8888)

Port of Old MT commit fec30e37ac
From: SmallJoker <SmallJoker@users.noreply.github.com>
Date: Sat, 21 Sep 2019 17:54:52 +0200
master
OldCoder 1 month ago
parent
commit
dfe0bebc34

+ 1
- 0
builtin/game/features.lua View File

@@ -11,6 +11,7 @@ core.features = {
area_store_custom_ids = true,
add_entity_with_staticdata = true,
no_chat_message_prediction = true,
area_store_persistent_ids = true,
}

function core.has_feature(arg)

+ 44
- 35
doc/lua_api.txt View File

@@ -2450,6 +2450,8 @@ Strings that need to be translated can contain several escapes, preceded by `@`.
-- ^ add_entity supports passing initial staticdata to on_activate
no_chat_message_prediction = true,
-- ^ Chat messages are no longer predicted
area_store_persistent_ids = true,
-- ^ Whether AreaStore IDs are kept on save/load (5.1.0)
}
* `minetest.has_feature(arg)`: returns `boolean, missing_features`
* `arg`: string or table in format `{foo=true, bar=true}`
@@ -3811,45 +3813,52 @@ An `InvRef` is a reference to an inventory.
* returns `{type="undefined"}` in case location is not known

### `AreaStore`
A fast access data structure to store areas, and find areas near a given position or area.

A fast access data structure to store areas, and find areas near a given
position or area.
Every area has a `data` string attribute to store additional information.
You can create an empty `AreaStore` by calling `AreaStore()`, or `AreaStore(type_name)`.
If you chose the parameter-less constructor, a fast implementation will be automatically
chosen for you.
You can create an empty `AreaStore` by calling `AreaStore()`, or
`AreaStore(type_name)`. The mod decides where to save and load AreaStore.
If you chose the parameter-less constructor, a fast implementation will be
automatically chosen for you.

#### Methods
* `get_area(id, include_borders, include_data)`: returns the area with the id `id`.
(optional) Boolean values `include_borders` and `include_data` control what's copied.
Returns nil if specified area id does not exist.
* `get_areas_for_pos(pos, include_borders, include_data)`: returns all areas that contain
the position `pos`. (optional) Boolean values `include_borders` and `include_data` control
what's copied.
* `get_areas_in_area(edge1, edge2, accept_overlap, include_borders, include_data)`:
returns all areas that contain all nodes inside the area specified by `edge1` and `edge2` (inclusive).
If `accept_overlap` is true, also areas are returned that have nodes in common with the specified area.
(optional) Boolean values `include_borders` and `include_data` control what's copied.
* `insert_area(edge1, edge2, data, [id])`: inserts an area into the store. Returns the new area's ID,
or nil if the insertion failed. The (inclusive) positions `edge1` and `edge2` describe the area.
`data` is a string stored with the area. If passed, `id` will be used as the internal area ID,
it must be a unique number between 0 and 2^32-2. If you use the `id` parameter you must always use it,
or insertions are likely to fail due to conflicts.
* `reserve(count)`: reserves resources for at most `count` many contained areas.

* `get_area(id, include_borders, include_data)`
* Returns the area information about the specified ID.
* Returned values are either of these:

nil -- Area not found
true -- Without `include_borders` and `include_data`
{
min = pos, max = pos -- `include_borders == true`
data = string -- `include_data == true`
}

* `get_areas_for_pos(pos, include_borders, include_data)`
* Returns all areas as table, indexed by the area ID.
* Table values: see `get_area`.

* `get_areas_in_area(edge1, edge2, accept_overlap, include_borders, include_data)`
* Returns all areas that contain all nodes inside the area specified by `edge1`
and `edge2` (inclusive).
* `accept_overlap`: if `true`, areas are returned that have nodes in
common (intersect) with the specified area.
* Returns the same values as `get_areas_for_pos`.

* `insert_area(edge1, edge2, data, [id])`: inserts an area into the store.
* Returns the new area's ID, or nil if the insertion failed.
* The (inclusive) positions `edge1` and `edge2` describe the area.
* `data` is a string stored with the area.
* `id` (optional): will be used as the internal area ID if it is an unique
number between 0 and 2^32-2.

* `reserve(count)`: reserves resources for at most `count` many contained
areas.
Only needed for efficiency, and only some implementations profit.
* `remove_area(id)`: removes the area with the given id from the store, returns success.
* `set_cache_params(params)`: sets params for the included prefiltering cache.
Calling invalidates the cache, so that its elements have to be newly generated.
* `params`:
{
enabled = boolean, -- whether to enable, default true
block_radius = number, -- the radius (in nodes) of the areas the cache generates
prefiltered lists for, minimum 16, default 64
limit = number, -- the cache's size, minimum 20, default 1000
}
* `to_string()`: Experimental. Returns area store serialized as a (binary) string.
* `to_file(filename)`: Experimental. Like `to_string()`, but writes the data to a file.
* `from_string(str)`: Experimental. Deserializes string and loads it into the AreaStore.
Returns success and, optionally, an error message.
* `from_file(filename)`: Experimental. Like `from_string()`, but reads the data from a file.

* `remove_area(id)`: removes the area with the given id from the store, returns
success.

### `ItemStack`
An `ItemStack` is a stack of items.

+ 1
- 0
src/script/lua_api/l_areastore.cpp View File

@@ -185,6 +185,7 @@ int LuaAreaStore::l_insert_area(lua_State *L)
if (lua_isnumber(L, 5))
a.id = lua_tonumber(L, 5);

// Insert & assign a new ID if necessary
if (!ast->insertArea(&a))
return 0;


+ 20
- 9
src/unittest/test_areastore.cpp View File

@@ -128,11 +128,11 @@ void TestAreaStore::testSerialization()
VectorAreaStore store;

Area a(v3s16(-1, 0, 1), v3s16(0, 1, 2));
a.data = "Area A";
a.data = "Area AA";
store.insertArea(&a);

Area b(v3s16(123, 456, 789), v3s16(32000, 100, 10));
b.data = "Area B";
b.data = "Area BB";
store.insertArea(&b);

std::ostringstream os;
@@ -143,19 +143,30 @@ void TestAreaStore::testSerialization()
"\x00\x02" // Count
"\xFF\xFF\x00\x00\x00\x01" // Area A min edge
"\x00\x00\x00\x01\x00\x02" // Area A max edge
"\x00\x06" // Area A data length
"Area A" // Area A data
"\x00\x07" // Area A data length
"Area AA" // Area A data
"\x00\x7B\x00\x64\x00\x0A" // Area B min edge (last two swapped with max edge for sorting)
"\x7D\x00\x01\xC8\x03\x15" // Area B max edge (^)
"\x00\x06" // Area B data length
"Area B", // Area B data
"\x00\x07" // Area B data length
"Area BB" // Area B data
"\x00\x00\x00\x00" // ID A = 0
"\x00\x00\x00\x01", // ID B = 1
1 + 2 +
6 + 6 + 2 + 6 +
6 + 6 + 2 + 6);
(6 + 6 + 2 + 7) * 2 + // min/max edge, length, data
2 * 4); // Area IDs

UASSERTEQ(const std::string &, str, str_wanted);

std::istringstream is(str);
store.deserialize(is);

UASSERTEQ(size_t, store.size(), 4); // deserialize() doesn't clear the store
// deserialize() doesn't clear the store
// But existing IDs are overridden
UASSERTEQ(size_t, store.size(), 2);

Area c(v3s16(33, -2, -6), v3s16(4, 77, -76));
c.data = "Area CC";
store.insertArea(&c);

UASSERTEQ(u32, c.id, 2);
}

+ 35
- 3
src/util/areastore.cpp View File

@@ -64,6 +64,11 @@ const Area *AreaStore::getArea(u32 id) const

void AreaStore::serialize(std::ostream &os) const
{
// WARNING:
// Before 5.1.0-dev: version != 0 throws SerializationError
// After 5.1.0-dev: version >= 5 throws SerializationError
// Forwards-compatibility is assumed before version 5.

writeU8(os, 0); // Serialisation version

// TODO: Compression?
@@ -76,27 +81,41 @@ void AreaStore::serialize(std::ostream &os) const
writeU16(os, a.data.size());
os.write(a.data.data(), a.data.size());
}

// Serialize IDs
for (const auto &it : areas_map)
writeU32(os, it.second.id);
}

void AreaStore::deserialize(std::istream &is)
{
u8 ver = readU8(is);
if (ver != 0)
// Assume forwards-compatibility before version 5
if (ver >= 5)
throw SerializationError("Unknown AreaStore "
"serialization version!");

u16 num_areas = readU16(is);
std::vector<Area> areas;
for (u32 i = 0; i < num_areas; ++i) {
Area a;
Area a(U32_MAX);
a.minedge = readV3S16(is);
a.maxedge = readV3S16(is);
u16 data_len = readU16(is);
char *data = new char[data_len];
is.read(data, data_len);
a.data = std::string(data, data_len);
insertArea(&a);
areas.emplace_back(a);
delete [] data;
}

bool read_ids = is.good(); // EOF for old formats

for (auto &area : areas) {
if (read_ids)
area.id = readU32(is);
insertArea(&area);
}
}

void AreaStore::invalidateCache()
@@ -106,6 +125,19 @@ void AreaStore::invalidateCache()
}
}

u32 AreaStore::getNextId() const
{
u32 free_id = 0;
for (const auto &area : areas_map) {
if (area.first > free_id)
return free_id; // Found gap

free_id = area.first + 1;
}
// End of map
return free_id;
}

void AreaStore::setCacheParams(bool enabled, u8 block_radius, size_t limit)
{
m_cache_enabled = enabled;

+ 9
- 10
src/util/areastore.h View File

@@ -36,22 +36,23 @@ with this program; if not, write to the Free Software Foundation, Inc.,
#include "util/serialize.h"
#endif

struct Area
{
Area(u32 area_id) : id(area_id) {}

struct Area {
Area() {}
Area(const v3s16 &mine, const v3s16 &maxe) :
minedge(mine), maxedge(maxe)
Area(const v3s16 &mine, const v3s16 &maxe, u32 area_id = U32_MAX) :
id(area_id), minedge(mine), maxedge(maxe)
{
sortBoxVerticies(minedge, maxedge);
}

u32 id = U32_MAX;
u32 id;
v3s16 minedge, maxedge;
std::string data;
};

class AreaStore {
class AreaStore
{
public:
AreaStore() :
m_res_cache(1000, &cacheMiss, this)
@@ -109,7 +110,7 @@ protected:
virtual void getAreasForPosImpl(std::vector<Area *> *result, v3s16 pos) = 0;

/// Returns the next area ID and increments it.
u32 getNextId() { return m_next_id++; }
u32 getNextId() const;

// Note: This can't be an unordered_map, since all
// references would be invalidated on rehash.
@@ -125,8 +126,6 @@ private:
/// If you modify this, call invalidateCache()
u8 m_cacheblock_radius = 64;
LRUCache<v3s16, std::vector<Area *> > m_res_cache;

u32 m_next_id = 0;
};



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