private void HandleErrorOnUpdate(UpdateDto dto)
{
if (IsNotOwnUpdate(dto))
{
_editor.ReloadDocument(dto.DocumentId);
}
}
public void UpdateRequest(string host, UpdateDto updateDto)
{
using (var cf = GetChannelFactory(host))
{
cf.CreateChannel().UpdateRequest(updateDto);
}
}
private bool MergePendingUpdate(Document document, UpdateDto updateDto, Tuple <string, bool[]> resultAppliedGivenUpdate)
{
var everythingOk = true;
var pendingUpdate = document.PendingUpdate;
if (pendingUpdate != null)
{
//will the pending update be applied after the given update?
if (MemberOfFirstUpdateIsNotOwnerAndHigherMember(pendingUpdate, updateDto))
{
everythingOk = MergePendingUpdateAfterGivenUpdate(updateDto, pendingUpdate);
}
else if (MemberOfFirstUpdateIsOwnerOrLowerMember(pendingUpdate, updateDto))
{
everythingOk = MergePendingUpdateBeforeGivenUpdate(document, updateDto, pendingUpdate,
resultAppliedGivenUpdate);
}
}
else
{
//no mergin needed, only update the editor
_editor.UpdateText(updateDto.DocumentId, resultAppliedGivenUpdate.Item1);
}
return(everythingOk);
}
private void MergeUpdate(Document document, UpdateDto updateDto)
{
var resultAppliedGivenUpdate = _diffMatchPatch.patch_apply(updateDto.Patch, document.Content);
if (CheckResultIsValidOtherwiseReOpen(resultAppliedGivenUpdate, updateDto.DocumentId))
{
if (MergePendingUpdate(document, updateDto, resultAppliedGivenUpdate))
{
UpdateDocument(document, updateDto, resultAppliedGivenUpdate);
}
}
//check whether we have an out of sync update which is based on the given update (so we could apply it as well)
if (document.OutOfSyncUpdate != null && IsFirstPreviousOfSecond(updateDto, document.OutOfSyncUpdate))
{
var outOfSynUpdate = document.OutOfSyncUpdate;
document.OutOfSyncUpdate = null;
MergeUpdate(document, outOfSynUpdate);
}
var outOfSyncAcknowledge = document.OutOfSyncAcknowledge;
if (outOfSyncAcknowledge != null && IsFirstPreviousOfSecond(updateDto, document.PendingUpdate))
{
ConfirmPendingUpdate(document, outOfSyncAcknowledge);
document.OutOfSyncAcknowledge = null;
}
}
private bool MergePendingUpdateBeforeGivenUpdate(Document document, UpdateDto updateDto, UpdateDto pendingUpdate, Tuple <string, bool[]> resultAppliedGivenUpdate)
{
// merging happens as follows, first apply pending patch on document, then given update = new content
// yet, since server has already applied given update we need to set pending's hash to the has of the update
// and we need to recompute the patch of the pending patch in order that we get the same text when the ACK follows
pendingUpdate.PreviousHash = updateDto.NewHash;
var documentId = updateDto.DocumentId;
var resultAppliedPendingUpdate = _diffMatchPatch.patch_apply(pendingUpdate.Patch, document.Content);
bool everythingOk = CheckResultIsValidOtherwiseReOpen(resultAppliedPendingUpdate, documentId);
if (everythingOk)
{
var resultAfterPatches = _diffMatchPatch.patch_apply(updateDto.Patch, resultAppliedPendingUpdate.Item1);
everythingOk = CheckResultIsValidOtherwiseReOpen(resultAfterPatches, documentId);
if (everythingOk)
{
//compute new patch for pendin gupdate
pendingUpdate.Patch = _diffMatchPatch.patch_make(resultAppliedGivenUpdate.Item1, resultAfterPatches.Item1);
// Merge screen and update -> screen is built up on pending update, thus create patch pending -> screen
// then apply patch to new content
var mergePatch = _diffMatchPatch.patch_make(resultAppliedPendingUpdate.Item1, _editor.GetText(documentId));
var resultMerge = _diffMatchPatch.patch_apply(mergePatch, resultAfterPatches.Item1);
everythingOk = CheckResultIsValidOtherwiseReOpen(resultMerge, documentId);
if (everythingOk)
{
_editor.UpdateText(documentId, resultMerge.Item1);
}
}
}
return(everythingOk);
}
public void UpdateRequest(string host, UpdateDto updateDto)
{
using (var cf = GetChannelFactory(host))
{
cf.CreateChannel().UpdateRequest(updateDto);
}
}
private void SendUpdateToDocumentOwner(Document document, UpdateDto dto)
{
try
{
_communication.UpdateRequest(document.OwnerHost, dto);
}
catch (EndpointNotFoundException)
{
_editor.ServerUnreachable(document.Id);
}
}
private void UpdateDocument(Document document, UpdateDto updateDto, Tuple <string, bool[]> resultAppliedGivenUpdate)
{
document.Content = resultAppliedGivenUpdate.Item1;
document.CurrentRevisionId = updateDto.NewRevisionId;
document.CurrentHash = GetHash(document.Content);
if (!document.CurrentHash.SequenceEqual(updateDto.NewHash))
{
//oho... should be the same, something went terribly wrong
ReOpenDocument(document.Id);
}
}
private UpdateDto CreateUpdateDto(Document document, string content)
{
var updateDto = new UpdateDto
{
DocumentId = document.Id,
PreviousRevisionId = document.CurrentRevisionId,
PreviousHash = document.CurrentHash,
Patch = _diffMatchPatch.patch_make(document.Content, content),
MemberName = _memberName,
MemberHost = _serverHost
};
return(updateDto);
}
private bool MergePendingUpdateAfterGivenUpdate(UpdateDto updateDto, UpdateDto pendingUpdate)
{
// it's enough to set the previous hash to the hash of the given update
pendingUpdate.PreviousHash = updateDto.NewHash;
// Merge screen and update
var documentId = updateDto.DocumentId;
var result = _diffMatchPatch.patch_apply(updateDto.Patch, _editor.GetText(documentId));
var everythingOk = CheckResultIsValidOtherwiseReOpen(result, documentId);
if (everythingOk)
{
_editor.UpdateText(documentId, result.Item1);
}
return(everythingOk);
}
private void ApplyUpdate(Document document, UpdateDto dto)
{
if (document.CurrentRevisionId == dto.PreviousRevisionId && document.CurrentHash.SequenceEqual(dto.PreviousHash))
{
MergeUpdate(document, dto);
}
else if (document.OutOfSyncUpdate == null)
{
//update out of sync. Got an update which is not based on previous revision
document.OutOfSyncUpdate = dto;
}
else
{
//too many out of sync updates, need to re-open the document
ReOpenDocument(dto.DocumentId);
}
}
public void UpdateRequest(UpdateDto dto)
{
//do we know such a document?
if (_documents.ContainsKey(dto.DocumentId))
{
var document = _documents[dto.DocumentId];
//I am the owner/server?
if (document.Owner == _memberName)
{
_editor.UpdateNumberOfEditors(document.Id, document.EditorCount);
CreatePatchForUpdate(document, dto);
}
else
{
_editor.UpdateNumberOfEditors(document.Id, dto.EditorCount);
ApplyUpdate(document, dto);
}
}
}
private UpdateDto CreateUpdateDto(Document document, string content)
{
var updateDto = new UpdateDto
{
DocumentId = document.Id,
PreviousRevisionId = document.CurrentRevisionId,
PreviousHash = document.CurrentHash,
Patch = _diffMatchPatch.patch_make(document.Content, content),
MemberName = _memberName,
MemberHost = _serverHost
};
return updateDto;
}
private bool MergePendingUpdate(Document document, UpdateDto updateDto, Tuple<string, bool[]> resultAppliedGivenUpdate)
{
var everythingOk = true;
var pendingUpdate = document.PendingUpdate;
if (pendingUpdate != null)
{
//will the pending update be applied after the given update?
if (MemberOfFirstUpdateIsNotOwnerAndHigherMember(pendingUpdate, updateDto))
{
everythingOk = MergePendingUpdateAfterGivenUpdate(updateDto, pendingUpdate);
}
else if (MemberOfFirstUpdateIsOwnerOrLowerMember(pendingUpdate, updateDto))
{
everythingOk = MergePendingUpdateBeforeGivenUpdate(document, updateDto, pendingUpdate,
resultAppliedGivenUpdate);
}
}
else
{
//no mergin needed, only update the editor
_editor.UpdateText(updateDto.DocumentId, resultAppliedGivenUpdate.Item1);
}
return everythingOk;
}
private bool IsFirstPreviousOfSecond(UpdateDto lastUpdate, UpdateDto updateDto)
{
return lastUpdate.NewRevisionId == updateDto.PreviousRevisionId &&
lastUpdate.NewHash.SequenceEqual(updateDto.PreviousHash);
}
private bool MergePendingUpdateAfterGivenUpdate(UpdateDto updateDto, UpdateDto pendingUpdate)
{
// it's enough to set the previous hash to the hash of the given update
pendingUpdate.PreviousHash = updateDto.NewHash;
// Merge screen and update
var documentId = updateDto.DocumentId;
var result = _diffMatchPatch.patch_apply(updateDto.Patch, _editor.GetText(documentId));
var everythingOk = CheckResultIsValidOtherwiseReOpen(result, documentId);
if (everythingOk)
{
_editor.UpdateText(documentId, result.Item1);
}
return everythingOk;
}
private bool IsNotOwnUpdate(UpdateDto updateDto)
{
return updateDto.MemberName != _memberName;
}
private bool MemberOfFirstUpdateIsOwnerOrLowerMember(UpdateDto firstUpdateDto, UpdateDto secondUpdateDto)
{
return(!IsNotOwnUpdate(firstUpdateDto) || string.Compare(firstUpdateDto.MemberName, secondUpdateDto.MemberName) < 0);
}
private bool MemberOfFirstUpdateIsNotOwnerAndHigherMember(UpdateDto firstUpdateDto, UpdateDto secondUpdateDto)
{
return(IsNotOwnUpdate(firstUpdateDto) && string.Compare(firstUpdateDto.MemberName, secondUpdateDto.MemberName) > 0);
}
private bool MemberOfFirstUpdateIsOwnerOrLowerMember(UpdateDto firstUpdateDto, UpdateDto secondUpdateDto)
{
return !IsNotOwnUpdate(firstUpdateDto) || string.Compare(firstUpdateDto.MemberName, secondUpdateDto.MemberName) < 0;
}
private bool IsNotOwnUpdate(UpdateDto updateDto)
{
return(updateDto.MemberName != _memberName);
}
private void HandleErrorOnUpdate(UpdateDto dto)
{
if (IsNotOwnUpdate(dto))
{
_editor.ReloadDocument(dto.DocumentId);
}
}
private bool MergePendingUpdateBeforeGivenUpdate(Document document, UpdateDto updateDto, UpdateDto pendingUpdate, Tuple<string, bool[]> resultAppliedGivenUpdate)
{
// merging happens as follows, first apply pending patch on document, then given update = new content
// yet, since server has already applied given update we need to set pending's hash to the has of the update
// and we need to recompute the patch of the pending patch in order that we get the same text when the ACK follows
pendingUpdate.PreviousHash = updateDto.NewHash;
var documentId = updateDto.DocumentId;
var resultAppliedPendingUpdate = _diffMatchPatch.patch_apply(pendingUpdate.Patch, document.Content);
bool everythingOk = CheckResultIsValidOtherwiseReOpen(resultAppliedPendingUpdate, documentId);
if (everythingOk)
{
var resultAfterPatches = _diffMatchPatch.patch_apply(updateDto.Patch, resultAppliedPendingUpdate.Item1);
everythingOk = CheckResultIsValidOtherwiseReOpen(resultAfterPatches, documentId);
if (everythingOk)
{
//compute new patch for pendin gupdate
pendingUpdate.Patch = _diffMatchPatch.patch_make(resultAppliedGivenUpdate.Item1, resultAfterPatches.Item1);
// Merge screen and update -> screen is built up on pending update, thus create patch pending -> screen
// then apply patch to new content
var mergePatch = _diffMatchPatch.patch_make(resultAppliedPendingUpdate.Item1, _editor.GetText(documentId));
var resultMerge = _diffMatchPatch.patch_apply(mergePatch, resultAfterPatches.Item1);
everythingOk = CheckResultIsValidOtherwiseReOpen(resultMerge, documentId);
if (everythingOk)
{
_editor.UpdateText(documentId, resultMerge.Item1);
}
}
}
return everythingOk;
}
private void UpdateDocument(Document document, UpdateDto updateDto, Tuple<string, bool[]> resultAppliedGivenUpdate)
{
document.Content = resultAppliedGivenUpdate.Item1;
document.CurrentRevisionId = updateDto.NewRevisionId;
document.CurrentHash = GetHash(document.Content);
if (!document.CurrentHash.SequenceEqual(updateDto.NewHash))
{
//oho... should be the same, something went terribly wrong
ReOpenDocument(document.Id);
}
}
private void SendUpdateToDocumentOwner(Document document, UpdateDto dto)
{
try
{
_communication.UpdateRequest(document.OwnerHost, dto);
}
catch (EndpointNotFoundException)
{
_editor.ServerUnreachable(document.Id);
}
}
private void MergeUpdate(Document document, UpdateDto updateDto)
{
var resultAppliedGivenUpdate = _diffMatchPatch.patch_apply(updateDto.Patch, document.Content);
if (CheckResultIsValidOtherwiseReOpen(resultAppliedGivenUpdate, updateDto.DocumentId))
{
if (MergePendingUpdate(document, updateDto, resultAppliedGivenUpdate))
{
UpdateDocument(document, updateDto, resultAppliedGivenUpdate);
}
}
//check whether we have an out of sync update which is based on the given update (so we could apply it as well)
if (document.OutOfSyncUpdate != null && IsFirstPreviousOfSecond(updateDto, document.OutOfSyncUpdate))
{
var outOfSynUpdate = document.OutOfSyncUpdate;
document.OutOfSyncUpdate = null;
MergeUpdate(document, outOfSynUpdate);
}
var outOfSyncAcknowledge = document.OutOfSyncAcknowledge;
if (outOfSyncAcknowledge != null && IsFirstPreviousOfSecond(updateDto, document.PendingUpdate))
{
ConfirmPendingUpdate(document, outOfSyncAcknowledge);
document.OutOfSyncAcknowledge = null;
}
}
private bool IsFirstPreviousOfSecond(UpdateDto lastUpdate, UpdateDto updateDto)
{
return(lastUpdate.NewRevisionId == updateDto.PreviousRevisionId &&
lastUpdate.NewHash.SequenceEqual(updateDto.PreviousHash));
}
private bool MemberOfFirstUpdateIsNotOwnerAndHigherMember(UpdateDto firstUpdateDto, UpdateDto secondUpdateDto)
{
return IsNotOwnUpdate(firstUpdateDto) && string.Compare(firstUpdateDto.MemberName, secondUpdateDto.MemberName) > 0;
}
private void ApplyUpdate(Document document, UpdateDto dto)
{
if (document.CurrentRevisionId == dto.PreviousRevisionId && document.CurrentHash.SequenceEqual(dto.PreviousHash))
{
MergeUpdate(document, dto);
}
else if (document.OutOfSyncUpdate == null)
{
//update out of sync. Got an update which is not based on previous revision
document.OutOfSyncUpdate = dto;
}
else
{
//too many out of sync updates, need to re-open the document
ReOpenDocument(dto.DocumentId);
}
}
private void CreatePatchForUpdate(Document document, UpdateDto updateDto)
{
var currentRevision = document.GetCurrentRevision();
var lastUpdate = currentRevision.UpdateDto;
//non existing revision - used as null object
var secondLastUpdate = new UpdateDto {NewRevisionId = -1};
if (document.CurrentRevisionId > FIRST_VALID_REVISON_ID)
{
secondLastUpdate=document.GetRevision(document.CurrentRevisionId - 1).UpdateDto;
}
bool creationSucessfull = false;
//update is either based on current version
//or on previous version where
// - the member which initialised the previous version was the owner itself
// - or a member with a lower member name (and thus the given update will be applied afterwards)
//)
if (IsFirstPreviousOfSecond(lastUpdate, updateDto) ||
(IsFirstPreviousOfSecond(secondLastUpdate, updateDto)
&& MemberOfFirstUpdateIsOwnerOrLowerMember(lastUpdate, updateDto)
)
)
{
var result = _diffMatchPatch.patch_apply(updateDto.Patch, document.Content);
if (result.Item2.All(x => x))
{
document.Content = result.Item1;
creationSucessfull = true;
}else
{
HandleErrorOnUpdate(updateDto);
}
}
else
{
var revision = document.GetRevision(updateDto.PreviousRevisionId);
if (revision.Id + SUPPORTED_NUM_OF_REACTIVE_UPDATES >= currentRevision.Id)
{
var nextRevision = document.GetRevision(revision.Id + 1);
//move to next revision as long as
while (
nextRevision.UpdateDto.PreviousHash.SequenceEqual(updateDto.PreviousHash)
&& MemberOfFirstUpdateIsNotOwnerAndHigherMember(updateDto, nextRevision.UpdateDto)
&& nextRevision.Id < currentRevision.Id)
{
revision = nextRevision;
nextRevision = document.GetRevision(nextRevision.Id + 1);
}
var content = revision.Content;
var tmpRevision = revision;
var patch = updateDto.Patch;
//apply all patches on top of the found revision
while (tmpRevision.Id <= currentRevision.Id)
{
var result = _diffMatchPatch.patch_apply(patch, content);
if (result.Item2.All(x => x))
{
content = result.Item1;
if (tmpRevision.Id == currentRevision.Id)
{
break;
}
tmpRevision = document.GetRevision(tmpRevision.Id + 1);
patch = tmpRevision.UpdateDto.Patch;
}
else
{
HandleErrorOnUpdate(updateDto);
}
}
document.Content = content;
updateDto.Patch = _diffMatchPatch.patch_make(currentRevision.Content, content);
creationSucessfull = true;
}
}
if (creationSucessfull)
{
document.CurrentRevisionId = currentRevision.Id + 1;
document.CurrentHash = GetHash(document.Content);
updateDto.NewRevisionId = document.CurrentRevisionId;
updateDto.NewHash = document.CurrentHash;
document.AddRevision(new Revision
{
Id = document.CurrentRevisionId,
Content = document.Content,
UpdateDto = updateDto
});
if (IsNotOwnUpdate(updateDto))
{
_editor.UpdateText(updateDto.DocumentId, document.Content);
var acknowledgeDto = new AcknowledgeDto
{
PreviousRevisionId = updateDto.PreviousRevisionId,
PreviousHash = updateDto.PreviousHash,
NewRevisionId = updateDto.NewRevisionId,
NewHash = updateDto.NewHash,
DocumentId = document.Id
};
_communication.AckRequest(updateDto.MemberHost, acknowledgeDto);
}
var newUpdateDto = new UpdateDto
{
DocumentId = document.Id,
MemberName = updateDto.MemberName,
MemberHost = _serverHost,
PreviousRevisionId = updateDto.PreviousRevisionId,
PreviousHash = updateDto.PreviousHash,
NewRevisionId = updateDto.NewRevisionId,
NewHash = updateDto.NewHash,
Patch = updateDto.Patch,
EditorCount = document.EditorCount
};
foreach (var editorHost in document.Editors().Values)
{
if (updateDto.MemberHost != editorHost)
{
try
{
_communication.UpdateRequest(editorHost, newUpdateDto);
}
catch (EndpointNotFoundException)
{
document.Editors().Remove(editorHost);
}
}
}
}
else if (IsNotOwnUpdate(updateDto))
{
HandleErrorOnUpdate(updateDto);
}
}
private void CreatePatchForUpdate(Document document, UpdateDto updateDto)
{
var currentRevision = document.GetCurrentRevision();
var lastUpdate = currentRevision.UpdateDto;
//non existing revision - used as null object
var secondLastUpdate = new UpdateDto {
NewRevisionId = -1
};
if (document.CurrentRevisionId > FIRST_VALID_REVISON_ID)
{
secondLastUpdate = document.GetRevision(document.CurrentRevisionId - 1).UpdateDto;
}
bool creationSucessfull = false;
//update is either based on current version
//or on previous version where
// - the member which initialised the previous version was the owner itself
// - or a member with a lower member name (and thus the given update will be applied afterwards)
//)
if (IsFirstPreviousOfSecond(lastUpdate, updateDto) ||
(IsFirstPreviousOfSecond(secondLastUpdate, updateDto) &&
MemberOfFirstUpdateIsOwnerOrLowerMember(lastUpdate, updateDto)
)
)
{
var result = _diffMatchPatch.patch_apply(updateDto.Patch, document.Content);
if (result.Item2.All(x => x))
{
document.Content = result.Item1;
creationSucessfull = true;
}
else
{
HandleErrorOnUpdate(updateDto);
}
}
else
{
var revision = document.GetRevision(updateDto.PreviousRevisionId);
if (revision.Id + SUPPORTED_NUM_OF_REACTIVE_UPDATES >= currentRevision.Id)
{
var nextRevision = document.GetRevision(revision.Id + 1);
//move to next revision as long as
while (
nextRevision.UpdateDto.PreviousHash.SequenceEqual(updateDto.PreviousHash) &&
MemberOfFirstUpdateIsNotOwnerAndHigherMember(updateDto, nextRevision.UpdateDto) &&
nextRevision.Id < currentRevision.Id)
{
revision = nextRevision;
nextRevision = document.GetRevision(nextRevision.Id + 1);
}
var content = revision.Content;
var tmpRevision = revision;
var patch = updateDto.Patch;
//apply all patches on top of the found revision
while (tmpRevision.Id <= currentRevision.Id)
{
var result = _diffMatchPatch.patch_apply(patch, content);
if (result.Item2.All(x => x))
{
content = result.Item1;
if (tmpRevision.Id == currentRevision.Id)
{
break;
}
tmpRevision = document.GetRevision(tmpRevision.Id + 1);
patch = tmpRevision.UpdateDto.Patch;
}
else
{
HandleErrorOnUpdate(updateDto);
}
}
document.Content = content;
updateDto.Patch = _diffMatchPatch.patch_make(currentRevision.Content, content);
creationSucessfull = true;
}
}
if (creationSucessfull)
{
document.CurrentRevisionId = currentRevision.Id + 1;
document.CurrentHash = GetHash(document.Content);
updateDto.NewRevisionId = document.CurrentRevisionId;
updateDto.NewHash = document.CurrentHash;
document.AddRevision(new Revision
{
Id = document.CurrentRevisionId,
Content = document.Content,
UpdateDto = updateDto
});
if (IsNotOwnUpdate(updateDto))
{
_editor.UpdateText(updateDto.DocumentId, document.Content);
var acknowledgeDto = new AcknowledgeDto
{
PreviousRevisionId = updateDto.PreviousRevisionId,
PreviousHash = updateDto.PreviousHash,
NewRevisionId = updateDto.NewRevisionId,
NewHash = updateDto.NewHash,
DocumentId = document.Id
};
_communication.AckRequest(updateDto.MemberHost, acknowledgeDto);
}
var newUpdateDto = new UpdateDto
{
DocumentId = document.Id,
MemberName = updateDto.MemberName,
MemberHost = _serverHost,
PreviousRevisionId = updateDto.PreviousRevisionId,
PreviousHash = updateDto.PreviousHash,
NewRevisionId = updateDto.NewRevisionId,
NewHash = updateDto.NewHash,
Patch = updateDto.Patch,
EditorCount = document.EditorCount
};
foreach (var editorHost in document.Editors().Values)
{
if (updateDto.MemberHost != editorHost)
{
try
{
_communication.UpdateRequest(editorHost, newUpdateDto);
}
catch (EndpointNotFoundException)
{
document.Editors().Remove(editorHost);
}
}
}
}
else if (IsNotOwnUpdate(updateDto))
{
HandleErrorOnUpdate(updateDto);
}
}
public void UpdateRequest(UpdateDto dto)
{
//do we know such a document?
if (_documents.ContainsKey(dto.DocumentId))
{
var document = _documents[dto.DocumentId];
//I am the owner/server?
if (document.Owner == _memberName)
{
_editor.UpdateNumberOfEditors(document.Id, document.EditorCount);
CreatePatchForUpdate(document, dto);
}
else
{
_editor.UpdateNumberOfEditors(document.Id, dto.EditorCount);
ApplyUpdate(document, dto);
}
}
}
