Move the functions for reading room state to a separate package. (#29)

This should:
    1) Make the input package a bit cleaner.
    2) Allow use to reuse the state reading code from the query package.
This commit is contained in:
Mark Haines 2017-03-08 15:10:26 +00:00 committed by GitHub
parent 84682b33c9
commit 1d18da1189
4 changed files with 245 additions and 228 deletions

View File

@ -2,12 +2,14 @@ package input
import (
"github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/dendrite/roomserver/state"
"github.com/matrix-org/dendrite/roomserver/types"
"github.com/matrix-org/gomatrixserverlib"
)
// A RoomEventDatabase has the storage APIs needed to store a room event.
type RoomEventDatabase interface {
state.RoomStateDatabase
// Stores a matrix room event in the database
StoreEvent(event gomatrixserverlib.Event, authEventNIDs []types.EventNID) (types.RoomNID, types.StateAtEvent, error)
// Lookup the state entries for a list of string event IDs
@ -24,12 +26,6 @@ type RoomEventDatabase interface {
// Returns an error if there is an error talking to the database
// or if the room state for the event IDs aren't in the database
StateAtEventIDs(eventIDs []string) ([]types.StateAtEvent, error)
// Lookup the numeric state data IDs for each numeric state snapshot ID
// The returned slice is sorted by numeric state snapshot ID.
StateBlockNIDs(stateNIDs []types.StateSnapshotNID) ([]types.StateBlockNIDList, error)
// Lookup the state data for each numeric state data ID
// The returned slice is sorted by numeric state data ID.
StateEntries(stateBlockNIDs []types.StateBlockNID) ([]types.StateEntryList, error)
// Store the room state at an event in the database
AddState(roomNID types.RoomNID, stateBlockNIDs []types.StateBlockNID, state []types.StateEntry) (types.StateSnapshotNID, error)
// Set the state at an event.

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@ -3,6 +3,7 @@ package input
import (
"bytes"
"github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/dendrite/roomserver/state"
"github.com/matrix-org/dendrite/roomserver/types"
"github.com/matrix-org/gomatrixserverlib"
)
@ -90,7 +91,7 @@ func doUpdateLatestEvents(
return err
}
removed, added, err := differenceBetweeenStateSnapshots(db, oldStateNID, newStateNID)
removed, added, err := state.DifferenceBetweeenStateSnapshots(db, oldStateNID, newStateNID)
if err != nil {
return err
}

View File

@ -2,10 +2,10 @@ package input
import (
"fmt"
"github.com/matrix-org/dendrite/roomserver/state"
"github.com/matrix-org/dendrite/roomserver/types"
"github.com/matrix-org/gomatrixserverlib"
"github.com/matrix-org/util"
"sort"
)
// calculateAndStoreState calculates a snapshot of the state of a room before an event.
@ -81,7 +81,7 @@ const maxStateBlockNIDs = 64
func calculateAndStoreStateAfterManyEvents(db RoomEventDatabase, roomNID types.RoomNID, prevStates []types.StateAtEvent) (types.StateSnapshotNID, error) {
// Conflict resolution.
// First stage: load the state after each of the prev events.
combined, err := loadCombinedStateAfterEvents(db, prevStates)
combined, err := state.LoadCombinedStateAfterEvents(db, prevStates)
if err != nil {
return 0, err
}
@ -114,169 +114,6 @@ func calculateAndStoreStateAfterManyEvents(db RoomEventDatabase, roomNID types.R
return db.AddState(roomNID, nil, state)
}
// differenceBetweeenStateSnapshots works out which state entries have been added and removed between two snapshots.
func differenceBetweeenStateSnapshots(db RoomEventDatabase, oldStateNID, newStateNID types.StateSnapshotNID) (
removed, added []types.StateEntry, err error,
) {
if oldStateNID == newStateNID {
// If the snapshot NIDs are the same then nothing has changed
return nil, nil, nil
}
var oldEntries []types.StateEntry
var newEntries []types.StateEntry
if oldStateNID != 0 {
oldEntries, err = loadStateAtSnapshot(db, oldStateNID)
if err != nil {
return nil, nil, err
}
}
if newStateNID != 0 {
newEntries, err = loadStateAtSnapshot(db, newStateNID)
if err != nil {
return nil, nil, err
}
}
var oldI int
var newI int
for {
switch {
case oldI == len(oldEntries):
// We've reached the end of the old entries.
// The rest of the new list must have been newly added.
added = append(added, newEntries[newI:]...)
return
case newI == len(newEntries):
// We've reached the end of the new entries.
// The rest of the old list must be have been removed.
removed = append(removed, oldEntries[oldI:]...)
return
case oldEntries[oldI] == newEntries[newI]:
// The entry is in both lists so skip over it.
oldI++
newI++
case oldEntries[oldI].LessThan(newEntries[newI]):
// The lists are sorted so the old entry being less than the new entry means that it only appears in the old list.
removed = append(removed, oldEntries[oldI])
oldI++
default:
// Reaching the default case implies that the new entry is less than the old entry.
// Since the lists are sorted this means that it only appears in the new list.
added = append(added, newEntries[newI])
newI++
}
}
}
// loadStateAtSnapshot loads the full state of a room at a particular snapshot.
// This is typically the state before an event or the current state of a room.
// Returns a sorted list of state entries or an error if there was a problem talking to the database.
func loadStateAtSnapshot(db RoomEventDatabase, stateNID types.StateSnapshotNID) ([]types.StateEntry, error) {
stateBlockNIDLists, err := db.StateBlockNIDs([]types.StateSnapshotNID{stateNID})
if err != nil {
return nil, err
}
stateBlockNIDList := stateBlockNIDLists[0]
stateEntryLists, err := db.StateEntries(stateBlockNIDList.StateBlockNIDs)
if err != nil {
return nil, err
}
stateEntriesMap := stateEntryListMap(stateEntryLists)
// Combined all the state entries for this snapshot.
// The order of state block NIDs in the list tells us the order to combine them in.
var fullState []types.StateEntry
for _, stateBlockNID := range stateBlockNIDList.StateBlockNIDs {
entries, ok := stateEntriesMap.lookup(stateBlockNID)
if !ok {
// This should only get hit if the database is corrupt.
// It should be impossible for an event to reference a NID that doesn't exist
panic(fmt.Errorf("Corrupt DB: Missing state block numeric ID %d", stateBlockNID))
}
fullState = append(fullState, entries...)
}
// Stable sort so that the most recent entry for each state key stays
// remains later in the list than the older entries for the same state key.
sort.Stable(stateEntryByStateKeySorter(fullState))
// Unique returns the last entry and hence the most recent entry for each state key.
fullState = fullState[:util.Unique(stateEntryByStateKeySorter(fullState))]
return fullState, nil
}
// loadCombinedStateAfterEvents loads a snapshot of the state after each of the events
// and combines those snapshots together into a single list.
func loadCombinedStateAfterEvents(db RoomEventDatabase, prevStates []types.StateAtEvent) ([]types.StateEntry, error) {
stateNIDs := make([]types.StateSnapshotNID, len(prevStates))
for i, state := range prevStates {
stateNIDs[i] = state.BeforeStateSnapshotNID
}
// Fetch the state snapshots for the state before the each prev event from the database.
// Deduplicate the IDs before passing them to the database.
// There could be duplicates because the events could be state events where
// the snapshot of the room state before them was the same.
stateBlockNIDLists, err := db.StateBlockNIDs(uniqueStateSnapshotNIDs(stateNIDs))
if err != nil {
return nil, err
}
var stateBlockNIDs []types.StateBlockNID
for _, list := range stateBlockNIDLists {
stateBlockNIDs = append(stateBlockNIDs, list.StateBlockNIDs...)
}
// Fetch the state entries that will be combined to create the snapshots.
// Deduplicate the IDs before passing them to the database.
// There could be duplicates because a block of state entries could be reused by
// multiple snapshots.
stateEntryLists, err := db.StateEntries(uniqueStateBlockNIDs(stateBlockNIDs))
if err != nil {
return nil, err
}
stateBlockNIDsMap := stateBlockNIDListMap(stateBlockNIDLists)
stateEntriesMap := stateEntryListMap(stateEntryLists)
// Combine the entries from all the snapshots of state after each prev event into a single list.
var combined []types.StateEntry
for _, prevState := range prevStates {
// Grab the list of state data NIDs for this snapshot.
stateBlockNIDs, ok := stateBlockNIDsMap.lookup(prevState.BeforeStateSnapshotNID)
if !ok {
// This should only get hit if the database is corrupt.
// It should be impossible for an event to reference a NID that doesn't exist
panic(fmt.Errorf("Corrupt DB: Missing state snapshot numeric ID %d", prevState.BeforeStateSnapshotNID))
}
// Combined all the state entries for this snapshot.
// The order of state block NIDs in the list tells us the order to combine them in.
var fullState []types.StateEntry
for _, stateBlockNID := range stateBlockNIDs {
entries, ok := stateEntriesMap.lookup(stateBlockNID)
if !ok {
// This should only get hit if the database is corrupt.
// It should be impossible for an event to reference a NID that doesn't exist
panic(fmt.Errorf("Corrupt DB: Missing state block numeric ID %d", stateBlockNID))
}
fullState = append(fullState, entries...)
}
if prevState.IsStateEvent() {
// If the prev event was a state event then add an entry for the event itself
// so that we get the state after the event rather than the state before.
fullState = append(fullState, prevState.StateEntry)
}
// Stable sort so that the most recent entry for each state key stays
// remains later in the list than the older entries for the same state key.
sort.Stable(stateEntryByStateKeySorter(fullState))
// Unique returns the last entry and hence the most recent entry for each state key.
fullState = fullState[:util.Unique(stateEntryByStateKeySorter(fullState))]
// Add the full state for this StateSnapshotNID.
combined = append(combined, fullState...)
}
return combined, nil
}
func resolveConflicts(db RoomEventDatabase, combined, conflicted []types.StateEntry) ([]types.StateEntry, error) {
panic(fmt.Errorf("Not implemented"))
}
@ -308,64 +145,8 @@ func findDuplicateStateKeys(a []types.StateEntry) []types.StateEntry {
return result
}
type stateBlockNIDListMap []types.StateBlockNIDList
func (m stateBlockNIDListMap) lookup(stateNID types.StateSnapshotNID) (stateBlockNIDs []types.StateBlockNID, ok bool) {
list := []types.StateBlockNIDList(m)
i := sort.Search(len(list), func(i int) bool {
return list[i].StateSnapshotNID >= stateNID
})
if i < len(list) && list[i].StateSnapshotNID == stateNID {
ok = true
stateBlockNIDs = list[i].StateBlockNIDs
}
return
}
type stateEntryListMap []types.StateEntryList
func (m stateEntryListMap) lookup(stateBlockNID types.StateBlockNID) (stateEntries []types.StateEntry, ok bool) {
list := []types.StateEntryList(m)
i := sort.Search(len(list), func(i int) bool {
return list[i].StateBlockNID >= stateBlockNID
})
if i < len(list) && list[i].StateBlockNID == stateBlockNID {
ok = true
stateEntries = list[i].StateEntries
}
return
}
type stateEntryByStateKeySorter []types.StateEntry
func (s stateEntryByStateKeySorter) Len() int { return len(s) }
func (s stateEntryByStateKeySorter) Less(i, j int) bool {
return s[i].StateKeyTuple.LessThan(s[j].StateKeyTuple)
}
func (s stateEntryByStateKeySorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
type stateEntrySorter []types.StateEntry
func (s stateEntrySorter) Len() int { return len(s) }
func (s stateEntrySorter) Less(i, j int) bool { return s[i].LessThan(s[j]) }
func (s stateEntrySorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
type stateNIDSorter []types.StateSnapshotNID
func (s stateNIDSorter) Len() int { return len(s) }
func (s stateNIDSorter) Less(i, j int) bool { return s[i] < s[j] }
func (s stateNIDSorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func uniqueStateSnapshotNIDs(nids []types.StateSnapshotNID) []types.StateSnapshotNID {
return nids[:util.SortAndUnique(stateNIDSorter(nids))]
}
type stateBlockNIDSorter []types.StateBlockNID
func (s stateBlockNIDSorter) Len() int { return len(s) }
func (s stateBlockNIDSorter) Less(i, j int) bool { return s[i] < s[j] }
func (s stateBlockNIDSorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func uniqueStateBlockNIDs(nids []types.StateBlockNID) []types.StateBlockNID {
return nids[:util.SortAndUnique(stateBlockNIDSorter(nids))]
}

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@ -0,0 +1,239 @@
// Package state provides functions for reading state from the database.
// The functions for writing state to the database are the input package.
package state
import (
"fmt"
"github.com/matrix-org/dendrite/roomserver/types"
"github.com/matrix-org/util"
"sort"
)
// A RoomStateDatabase has the storage APIs needed to load state from the database
type RoomStateDatabase interface {
// Lookup the numeric state data IDs for each numeric state snapshot ID
// The returned slice is sorted by numeric state snapshot ID.
StateBlockNIDs(stateNIDs []types.StateSnapshotNID) ([]types.StateBlockNIDList, error)
// Lookup the state data for each numeric state data ID
// The returned slice is sorted by numeric state data ID.
StateEntries(stateBlockNIDs []types.StateBlockNID) ([]types.StateEntryList, error)
}
// LoadStateAtSnapshot loads the full state of a room at a particular snapshot.
// This is typically the state before an event or the current state of a room.
// Returns a sorted list of state entries or an error if there was a problem talking to the database.
func LoadStateAtSnapshot(db RoomStateDatabase, stateNID types.StateSnapshotNID) ([]types.StateEntry, error) {
stateBlockNIDLists, err := db.StateBlockNIDs([]types.StateSnapshotNID{stateNID})
if err != nil {
return nil, err
}
stateBlockNIDList := stateBlockNIDLists[0]
stateEntryLists, err := db.StateEntries(stateBlockNIDList.StateBlockNIDs)
if err != nil {
return nil, err
}
stateEntriesMap := stateEntryListMap(stateEntryLists)
// Combined all the state entries for this snapshot.
// The order of state block NIDs in the list tells us the order to combine them in.
var fullState []types.StateEntry
for _, stateBlockNID := range stateBlockNIDList.StateBlockNIDs {
entries, ok := stateEntriesMap.lookup(stateBlockNID)
if !ok {
// This should only get hit if the database is corrupt.
// It should be impossible for an event to reference a NID that doesn't exist
panic(fmt.Errorf("Corrupt DB: Missing state block numeric ID %d", stateBlockNID))
}
fullState = append(fullState, entries...)
}
// Stable sort so that the most recent entry for each state key stays
// remains later in the list than the older entries for the same state key.
sort.Stable(stateEntryByStateKeySorter(fullState))
// Unique returns the last entry and hence the most recent entry for each state key.
fullState = fullState[:util.Unique(stateEntryByStateKeySorter(fullState))]
return fullState, nil
}
// LoadCombinedStateAfterEvents loads a snapshot of the state after each of the events
// and combines those snapshots together into a single list.
func LoadCombinedStateAfterEvents(db RoomStateDatabase, prevStates []types.StateAtEvent) ([]types.StateEntry, error) {
stateNIDs := make([]types.StateSnapshotNID, len(prevStates))
for i, state := range prevStates {
stateNIDs[i] = state.BeforeStateSnapshotNID
}
// Fetch the state snapshots for the state before the each prev event from the database.
// Deduplicate the IDs before passing them to the database.
// There could be duplicates because the events could be state events where
// the snapshot of the room state before them was the same.
stateBlockNIDLists, err := db.StateBlockNIDs(uniqueStateSnapshotNIDs(stateNIDs))
if err != nil {
return nil, err
}
var stateBlockNIDs []types.StateBlockNID
for _, list := range stateBlockNIDLists {
stateBlockNIDs = append(stateBlockNIDs, list.StateBlockNIDs...)
}
// Fetch the state entries that will be combined to create the snapshots.
// Deduplicate the IDs before passing them to the database.
// There could be duplicates because a block of state entries could be reused by
// multiple snapshots.
stateEntryLists, err := db.StateEntries(uniqueStateBlockNIDs(stateBlockNIDs))
if err != nil {
return nil, err
}
stateBlockNIDsMap := stateBlockNIDListMap(stateBlockNIDLists)
stateEntriesMap := stateEntryListMap(stateEntryLists)
// Combine the entries from all the snapshots of state after each prev event into a single list.
var combined []types.StateEntry
for _, prevState := range prevStates {
// Grab the list of state data NIDs for this snapshot.
stateBlockNIDs, ok := stateBlockNIDsMap.lookup(prevState.BeforeStateSnapshotNID)
if !ok {
// This should only get hit if the database is corrupt.
// It should be impossible for an event to reference a NID that doesn't exist
panic(fmt.Errorf("Corrupt DB: Missing state snapshot numeric ID %d", prevState.BeforeStateSnapshotNID))
}
// Combined all the state entries for this snapshot.
// The order of state block NIDs in the list tells us the order to combine them in.
var fullState []types.StateEntry
for _, stateBlockNID := range stateBlockNIDs {
entries, ok := stateEntriesMap.lookup(stateBlockNID)
if !ok {
// This should only get hit if the database is corrupt.
// It should be impossible for an event to reference a NID that doesn't exist
panic(fmt.Errorf("Corrupt DB: Missing state block numeric ID %d", stateBlockNID))
}
fullState = append(fullState, entries...)
}
if prevState.IsStateEvent() {
// If the prev event was a state event then add an entry for the event itself
// so that we get the state after the event rather than the state before.
fullState = append(fullState, prevState.StateEntry)
}
// Stable sort so that the most recent entry for each state key stays
// remains later in the list than the older entries for the same state key.
sort.Stable(stateEntryByStateKeySorter(fullState))
// Unique returns the last entry and hence the most recent entry for each state key.
fullState = fullState[:util.Unique(stateEntryByStateKeySorter(fullState))]
// Add the full state for this StateSnapshotNID.
combined = append(combined, fullState...)
}
return combined, nil
}
// DifferenceBetweeenStateSnapshots works out which state entries have been added and removed between two snapshots.
func DifferenceBetweeenStateSnapshots(db RoomStateDatabase, oldStateNID, newStateNID types.StateSnapshotNID) (
removed, added []types.StateEntry, err error,
) {
if oldStateNID == newStateNID {
// If the snapshot NIDs are the same then nothing has changed
return nil, nil, nil
}
var oldEntries []types.StateEntry
var newEntries []types.StateEntry
if oldStateNID != 0 {
oldEntries, err = LoadStateAtSnapshot(db, oldStateNID)
if err != nil {
return nil, nil, err
}
}
if newStateNID != 0 {
newEntries, err = LoadStateAtSnapshot(db, newStateNID)
if err != nil {
return nil, nil, err
}
}
var oldI int
var newI int
for {
switch {
case oldI == len(oldEntries):
// We've reached the end of the old entries.
// The rest of the new list must have been newly added.
added = append(added, newEntries[newI:]...)
return
case newI == len(newEntries):
// We've reached the end of the new entries.
// The rest of the old list must be have been removed.
removed = append(removed, oldEntries[oldI:]...)
return
case oldEntries[oldI] == newEntries[newI]:
// The entry is in both lists so skip over it.
oldI++
newI++
case oldEntries[oldI].LessThan(newEntries[newI]):
// The lists are sorted so the old entry being less than the new entry means that it only appears in the old list.
removed = append(removed, oldEntries[oldI])
oldI++
default:
// Reaching the default case implies that the new entry is less than the old entry.
// Since the lists are sorted this means that it only appears in the new list.
added = append(added, newEntries[newI])
newI++
}
}
}
type stateBlockNIDListMap []types.StateBlockNIDList
func (m stateBlockNIDListMap) lookup(stateNID types.StateSnapshotNID) (stateBlockNIDs []types.StateBlockNID, ok bool) {
list := []types.StateBlockNIDList(m)
i := sort.Search(len(list), func(i int) bool {
return list[i].StateSnapshotNID >= stateNID
})
if i < len(list) && list[i].StateSnapshotNID == stateNID {
ok = true
stateBlockNIDs = list[i].StateBlockNIDs
}
return
}
type stateEntryListMap []types.StateEntryList
func (m stateEntryListMap) lookup(stateBlockNID types.StateBlockNID) (stateEntries []types.StateEntry, ok bool) {
list := []types.StateEntryList(m)
i := sort.Search(len(list), func(i int) bool {
return list[i].StateBlockNID >= stateBlockNID
})
if i < len(list) && list[i].StateBlockNID == stateBlockNID {
ok = true
stateEntries = list[i].StateEntries
}
return
}
type stateEntryByStateKeySorter []types.StateEntry
func (s stateEntryByStateKeySorter) Len() int { return len(s) }
func (s stateEntryByStateKeySorter) Less(i, j int) bool {
return s[i].StateKeyTuple.LessThan(s[j].StateKeyTuple)
}
func (s stateEntryByStateKeySorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
type stateNIDSorter []types.StateSnapshotNID
func (s stateNIDSorter) Len() int { return len(s) }
func (s stateNIDSorter) Less(i, j int) bool { return s[i] < s[j] }
func (s stateNIDSorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func uniqueStateSnapshotNIDs(nids []types.StateSnapshotNID) []types.StateSnapshotNID {
return nids[:util.SortAndUnique(stateNIDSorter(nids))]
}
type stateBlockNIDSorter []types.StateBlockNID
func (s stateBlockNIDSorter) Len() int { return len(s) }
func (s stateBlockNIDSorter) Less(i, j int) bool { return s[i] < s[j] }
func (s stateBlockNIDSorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func uniqueStateBlockNIDs(nids []types.StateBlockNID) []types.StateBlockNID {
return nids[:util.SortAndUnique(stateBlockNIDSorter(nids))]
}