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* fcl-db: cosmetic: bufdataset comments: typos, grammar, uniform indentation

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git-svn-id: trunk@23530 -
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reiniero 2013-01-28 15:49:05 +00:00
parent bb00325d85
commit b44353777a
1 changed files with 89 additions and 93 deletions
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76
packages/fcl-db/src/base/bufdataset.pas
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@ -1,6 +1,6 @@
{
This file is part of the Free Pascal run time library.
Copyright (c) 1999-2006 by Joost van der Sluis, member of the
Copyright (c) 1999-2013 by Joost van der Sluis and other members of the
Free Pascal development team
BufDataset implementation
@ -70,19 +70,19 @@ type
TRecUpdateBuffer = record
UpdateKind : TUpdateKind;
{ BookMarkData:
- Is -1 if the update has canceled out. For example: a appended record has been deleted again
- If UpdateKind is ukInsert it contains a bookmark to the new created record
- If UpdateKind is ukModify it contains a bookmark to the record with the new data
- If UpdateKind is ukDelete it contains a bookmark to the deleted record (ie: the record is still there)
- Is -1 if the update has canceled out. For example: an appended record has been deleted again
- If UpdateKind is ukInsert, it contains a bookmark to the newly created record
- If UpdateKind is ukModify, it contains a bookmark to the record with the new data
- If UpdateKind is ukDelete, it contains a bookmark to the deleted record (ie: the record is still there)
}
BookmarkData : TBufBookmark;
{ NextBookMarkData:
- If UpdateKind is ukDelete it contains a bookmark to the record just after the deleted record
- If UpdateKind is ukDelete, it contains a bookmark to the record just after the deleted record
}
NextBookmarkData : TBufBookmark;
{ OldValuesBuffer:
- If UpdateKind is ukModify it contains a record-buffer which contains the old data
- If UpdateKind is ukDelete it contains a record-buffer with the data of the deleted record
- If UpdateKind is ukModify, it contains a record buffer which contains the old data
- If UpdateKind is ukDelete, it contains a record buffer with the data of the deleted record
}
OldValuesBuffer : TRecordBuffer;
end;
@ -90,7 +90,7 @@ type
PBufBlobField = ^TBufBlobField;
TBufBlobField = record
ConnBlobBuffer : array[0..11] of byte; // It's here where the db-specific data is stored
ConnBlobBuffer : array[0..11] of byte; // DB specific data is stored here
BlobBuffer : PBlobBuffer;
end;
@ -159,7 +159,7 @@ type
// Normally only used in GetNextPacket
procedure AddRecord; virtual; abstract;
// Inserts a record before the current record, or if the record is sorted,
// insert it to the proper position
// inserts it in the proper position
procedure InsertRecordBeforeCurrentRecord(Const ARecord : TRecordBuffer); virtual; abstract;
procedure EndUpdate; virtual; abstract;
@ -352,7 +352,7 @@ type
public
constructor create(AStream : TStream); virtual;
// Load a dataset from stream:
// Load the field-definitions from a stream.
// Load the field definitions from a stream.
procedure LoadFieldDefs(AFieldDefs : TFieldDefs; var AnAutoIncValue : integer); virtual; abstract;
// Is called before the records are loaded
procedure InitLoadRecords; virtual; abstract;
@ -360,15 +360,15 @@ type
function GetRecordRowState(out AUpdOrder : Integer) : TRowState; virtual; abstract;
// Returns if there is at least one more record available in the stream
function GetCurrentRecord : boolean; virtual; abstract;
// Store a record from stream in the current record-buffer
// Store a record from stream in the current record buffer
procedure RestoreRecord(ADataset : TCustomBufDataset); virtual; abstract;
// Move the stream to the next record
procedure GotoNextRecord; virtual; abstract;
// Store a dataset to stream:
// Save the field-definitions to a stream.
// Save the field definitions to a stream.
procedure StoreFieldDefs(AFieldDefs : TFieldDefs; AnAutoIncValue : integer); virtual; abstract;
// Save a record from the current record-buffer to the stream
// Save a record from the current record buffer to the stream
procedure StoreRecord(ADataset : TCustomBufDataset; ARowState : TRowState; AUpdOrder : integer = 0); virtual; abstract;
// Is called after all records are stored
procedure FinalizeStoreRecords; virtual; abstract;
@ -805,7 +805,7 @@ begin
end;
{
// Code to dump raw dataset data, including indexes information, usefull for debugging
// Code to dump raw dataset data, including indexes information, useful for debugging
procedure DumpRawMem(const Data: pointer; ALength: PtrInt);
var
b: integer;
@ -986,7 +986,6 @@ begin
// So we start by pointing a temporary pointer p at the head of the list,
// and also preparing an empty list L which we will add elements to the end
// of as we finish dealing with them.
p := DblLinkIndex.FFirstRecBuf;
DblLinkIndex.FFirstRecBuf := nil;
q := p;
@ -999,13 +998,11 @@ begin
// * Otherwise, there is at least one element in the next pair of length-K
// lists, so increment the number of merges performed in this pass.
inc(MergeAmount);
// * Point another temporary pointer, q, at the same place as p. Step q along
// the list by K places, or until the end of the list, whichever comes
// first. Let psize be the number of elements you managed to step q past.
i:=0;
while (i<k) and (q<>DblLinkIndex.FLastRecBuf) do
begin
@ -1016,15 +1013,13 @@ begin
// * Let qsize equal K. Now we need to merge a list starting at p, of length
// psize, with a list starting at q of length at most qsize.
qsize:=k;
// * So, as long as either the p-list is non-empty (psize > 0) or the q-list
// is non-empty (qsize > 0 and q points to something non-null):
while (psize>0) or ((qsize>0) and (q <> DblLinkIndex.FLastRecBuf)) do
begin
// o Choose which list to take the next element from. If either list
// * Choose which list to take the next element from. If either list
// is empty, we must choose from the other one. (By assumption, at
// least one is non-empty at this point.) If both lists are
// non-empty, compare the first element of each and choose the lower
@ -1040,14 +1035,15 @@ begin
else
PlaceQRec := True;
// o Remove that element, e, from the start of its list, by advancing
// * Remove that element, e, from the start of its list, by advancing
// p or q to the next element along, and decrementing psize or qsize.
// o Add e to the end of the list L we are building up.
// * Add e to the end of the list L we are building up.
if PlaceQRec then
PlaceNewRec(q,qsize)
else
PlaceNewRec(p,psize);
end;
// * Now we have advanced p until it is where q started out, and we have
// advanced q until it is pointing at the next pair of length-K lists to
// merge. So set p to the value of q, and go back to the start of this loop.
@ -1138,7 +1134,7 @@ begin
// is not (correctly) created.
// commented for now. If there are constant expressions in the select
// statement they are ftunknown, and not created.
// statement they are ftUnknown, and not created.
// See mantis #22030
// if Fields.Count<FieldDefs.Count then
@ -1790,7 +1786,7 @@ end;
function TCustomBufDataset.GetRecordUpdateBufferCached(const ABookmark: TBufBookmark;
IncludePrior: boolean): boolean;
begin
// if the current update buffer complies, immediately return true
// if the current update buffer matches, immediately return true
if (FCurrentUpdateBuffer < length(FUpdateBuffer)) and (
FCurrentIndex.CompareBookmarks(@FUpdateBuffer[FCurrentUpdateBuffer].BookmarkData,@ABookmark) or
(IncludePrior and (FUpdateBuffer[FCurrentUpdateBuffer].UpdateKind=ukDelete) and FCurrentIndex.CompareBookmarks(@FUpdateBuffer[FCurrentUpdateBuffer].NextBookmarkData,@ABookmark))) then
@ -1969,11 +1965,11 @@ begin
if FUpdateBuffer[FCurrentUpdateBuffer].UpdateKind <> ukModify then
begin
FUpdateBuffer[FCurrentUpdateBuffer].OldValuesBuffer := nil; //this 'disables' the updatebuffer
// Do NOT release record buffer (pointed by RemRecBookmrk.BookmarkData) here
// - When record is inserted and deleted(and memory released) and again inserted then same memory block can be returned
// which leads to confusion, because we get same BookmarkData for distinct records
// - In CancelUpdates when records are restored it is expected, that deleted records still exists in memory
// There also could be record(s) in update-buffer, linked to this record.
// Do NOT release record buffer (pointed to by RemRecBookmrk.BookmarkData) here
// - When record is inserted and deleted (and memory released) and again inserted then the same memory block can be returned
// which leads to confusion, because we get the same BookmarkData for distinct records
// - In CancelUpdates when records are restored, it is expected that deleted records still exist in memory
// There also could be record(s) in the update buffer that is linked to this record.
end;
end;
FCurrentIndex.StoreCurrentRecIntoBookmark(@FUpdateBuffer[FCurrentUpdateBuffer].NextBookmarkData);
@ -2022,7 +2018,7 @@ var StoreRecBM : TBufBookmark;
end
else if (UpdateKind = ukInsert) then
begin
// Process all upd-buffers linked to this record before this record is removed
// Process all update buffers linked to this record before this record is removed
StoreUpdBuf:=FCurrentUpdateBuffer;
Bm := BookmarkData;
BookmarkData.BookmarkData:=nil; // Avoid infinite recursion...
@ -2078,7 +2074,7 @@ begin
FOnUpdateError := AValue;
end;
procedure TCustomBufDataset.ApplyUpdates; // For backwards-compatibility
procedure TCustomBufDataset.ApplyUpdates; // For backward compatibility
begin
ApplyUpdates(0);
@ -2246,7 +2242,7 @@ begin
FIndexes[i].GotoBookmark(ABookmark);
FIndexes[i].InsertRecordBeforeCurrentRecord(ABuff);
// new inserted record becomes current record
// newly inserted record becomes current record
FIndexes[i].ScrollBackward;
end;
@ -2629,7 +2625,7 @@ procedure TCustomBufDataset.GetDatasetPacket(AWriter: TDataPacketReader);
ARowState := [rsvInserted];
FFilterBuffer:=AUpdBuffer.OldValuesBuffer;
// If the record is inserted or inserted and afterwards deleted then OldValuesBuffer is nil
// OldValuesBuffer is nil if the record is either inserted or inserted and then deleted
if assigned(FFilterBuffer) then
FDatasetReader.StoreRecord(Self,AThisRowState,FCurrentUpdateBuffer);
end;
@ -2690,7 +2686,7 @@ begin
ScrollResult := FCurrentIndex.ScrollForward;
end;
end;
// There could be a update-buffer linked to the last (spare) record
// There could be an update buffer linked to the last (spare) record
FCurrentIndex.StoreSpareRecIntoBookmark(ABookmark);
HandleUpdateBuffersFromRecord(True,ABookmark^,RowState);
@ -3043,7 +3039,7 @@ begin
begin
FParser := TBufDatasetParser.Create(Self);
end;
// have a parser now?
// is there a parser now?
if FParser <> nil then
begin
// set options
@ -3120,7 +3116,7 @@ begin
SearchFields.Free;
end;
// Set The filter-buffer
// Set the filter buffer
StoreDSState:=SetTempState(dsFilter);
FFilterBuffer:=FCurrentIndex.SpareBuffer;
SetFieldValues(keyfields,KeyValues);
@ -3136,7 +3132,7 @@ begin
if Filtered then
begin
FFilterBuffer:=pointer(CurrLinkItem)+(sizeof(TBufRecLinkItem)*MaxIndexesCount);
// The dataset-state is still dsFilter at this point, so we don't have to set it.
// The dataset state is still dsFilter at this point, so we don't have to set it.
DoFilterRecord(FiltAcceptable);
if FiltAcceptable then
begin
@ -3550,7 +3546,7 @@ begin
// This code could be moved to the TBufIndex but that would make things
// more complicated and probably slower. So use a 'fake' bookmark of
// size TBufBookmark.
// When there are other TBufIndexes which also need special bookmark-code
// When there are other TBufIndexes which also need special bookmark code
// this can be adapted.
Result:=sizeof(TBufBookmark);
end;
@ -3628,7 +3624,7 @@ end;
function TUniDirectionalBufIndex.CanScrollForward: Boolean;
begin
// should return true if a next record is already fetched
// should return true if next record is already fetched
result := false;
end;