mirror of
https://gitlab.com/freepascal.org/fpc/source.git
synced 2025-05-22 06:52:32 +02:00
265923a2ee
Derek (mantis #28830) o ability for a thread to acquire a readlock when it already holds a write lock, or vice versa o detect when thread1 releases a lock while it hadn't acquired one o correct result of beginwrite (return true only when another thread held/acquired a write lock before the current thread got it) o extra compared to Derek's patch: replaced some additional (mostly pre-existing) interlocked*() hacks with proper memory barriers, made formatting consistent, fixed compilation on platforms where tthreadid is not an integer type, improved tthreadid hashing function for 64 bit platforms, fixed some comments git-svn-id: trunk@34678 -
68 lines
2.1 KiB
PHP
68 lines
2.1 KiB
PHP
{
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This file is part of the Free Pascal run time library.
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Copyright (c) 1999-2001 by the Free Pascal development team
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See the file COPYING.FPC, included in this distribution,
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for details about the copyright.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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**********************************************************************}
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type
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IReadWriteSync = interface
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{$ifdef FPC_HAS_FEATURE_THREADING}
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['{7B108C52-1D8F-4CDB-9CDF-57E071193D3F}']
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procedure BeginRead;
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procedure EndRead;
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function BeginWrite : boolean;
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procedure EndWrite;
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{$endif FPC_HAS_FEATURE_THREADING}
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end;
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TSimpleRWSync = class(TInterfacedObject,IReadWriteSync)
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{$ifdef FPC_HAS_FEATURE_THREADING}
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private
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crit : TRtlCriticalSection;
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public
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constructor Create; virtual;
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destructor Destroy; override;
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function Beginwrite : boolean;
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procedure Endwrite;
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procedure Beginread;
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procedure Endread;
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{$endif FPC_HAS_FEATURE_THREADING}
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end;
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TMultiReadExclusiveWriteSynchronizer = class(TInterfacedObject,IReadWriteSync)
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{$ifdef FPC_HAS_FEATURE_THREADING}
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private
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fThreadList: array [0..15] of Pointer;
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freaderqueue: peventstate;
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fwritelock : TRtlCriticalSection;
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fwaitingwriterlock: prtlevent;
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fWriterThreadID: TThreadID;
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fRevisionLevel: cardinal;
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fwriterequests: cardinal;
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factivethreads: cardinal;
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protected
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function ThreadIDtoIndex( aThreadID: TThreadID ): integer; inline;
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function GetThreadInfo(AutoCreate: Boolean): Pointer;
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procedure RemoveThread(AThreadInfo: Pointer);
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public
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constructor Create; virtual;
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destructor Destroy; override;
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function Beginwrite : boolean;
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procedure Endwrite;
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procedure Beginread;
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procedure Endread;
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property RevisionLevel: cardinal read fRevisionLevel;
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property WriterThreadID: TThreadID read fWriterThreadID;
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{$endif FPC_HAS_FEATURE_THREADING}
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end;
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TMREWException = class(Exception);
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