[Delphi] delphi线程池【转】

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2009-04-22 23:22 |只看楼主 发表者

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实现代码

unit uThreadPool;
{ aPool.AddRequest(TMyRequest.Create(RequestParam1, RequestParam2, ...)); }
interface
uses
Windows,
Classes;
// 是否记录日志
// {$DEFINE NOLOGS}
type
TCriticalSection = class(TObject)
protected
FSection: TRTLCriticalSection;
public
constructor Create;
destructor Destroy; override;
// 进入临界区
procedure Enter;
// 离开临界区
procedure Leave;
// 尝试进入
function TryEnter: Boolean;
end;
type
// 储存请求数据的基本类
TWorkItem = class(TObject)
public
// 是否有重复任务
function IsTheSame(DataObj: TWorkItem): Boolean; virtual;
// 如果 NOLOGS 被定义，则禁用。
function TextForLog: string; virtual;
end;
type
TThreadsPool = class;
//线程状态
TThreadState = (tcsInitializing, tcsWaiting, tcsGetting, tcsProcessing,
tcsProcessed, tcsTerminating, tcsCheckingDown);
// 工作线程仅用于线程池内，不要直接创建并调用它。
TProcessorThread = class(TThread)
*******
// 创建线程时临时的Event对象, 阻塞线程直到初始化完成
hInitFinished: THandle;
// 初始化出错信息
sInitError: string;
// 记录日志
procedure WriteLog(const Str: string; Level: Integer = 0);
protected
// 线程临界区同步对像
csProcessingDataObject: TCriticalSection;
// 平均处理时间
FAverageProcessing: Integer;
// 等待请求的平均时间
FAverageWaitingTime: Integer;
// 本线程实例的运行状态
FCurState: TThreadState;
// 本线程实例所附属的线程池
FPool: TThreadsPool;
// 当前处理的数据对像。
FProcessingDataObject: TWorkItem;
// 线程停止 Event, TProcessorThread.Terminate 中开绿灯
hThreadTerminated: THandle;
uProcessingStart: DWORD;
// 开始等待的时间, 通过 GetTickCount 取得。
uWaitingStart: DWORD;
// 计算平均工作时间
function AverageProcessingTime: DWORD;
// 计算平均等待时间
function AverageWaitingTime: DWORD;
procedure Execute; override;
function IamCurrentlyProcess(DataObj: TWorkItem): Boolean;
// 转换枚举类型的线程状态为字串类型
function InfoText: string;
// 线程是否长时间处理同一个请求？（已死掉？）
function IsDead: Boolean;
// 线程是否已完成当成任务
function isFinished: Boolean;
// 线程是否处于空闲状态
function isIdle: Boolean;
// 平均值校正计算。
function NewAverage(OldAvg, NewVal: Integer): Integer;
public
Tag: Integer;
constructor Create(APool: TThreadsPool);
destructor Destroy; override;
procedure Terminate;
end;
// 线程初始化时触发的事件
TProcessorThreadInitializing = procedure(Sender: TThreadsPool; aThread:
TProcessorThread) of object;
// 线程结束时触发的事件
TProcessorThreadFinalizing = procedure(Sender: TThreadsPool; aThread:
TProcessorThread) of object;
// 线程处理请求时触发的事件
TProcessRequest = procedure(Sender: TThreadsPool; WorkItem: TWorkItem;
aThread: TProcessorThread) of object;
TEmptyKind = (
ekQueueEmpty, //任务被取空后
ekProcessingFinished // 最后一个任务处理完毕后
);
// 任务队列空时触发的事件
TQueueEmpty = procedure(Sender: TThreadsPool; EmptyKind: TEmptyKind) of
object;
TThreadsPool = class(TComponent)
*******
csQueueManagment: TCriticalSection;
csThreadManagment: TCriticalSection;
FProcessRequest: TProcessRequest;
FQueue: TList;
FQueueEmpty: TQueueEmpty;
// 线程超时阀值
FThreadDeadTimeout: DWORD;
FThreadFinalizing: TProcessorThreadFinalizing;
FThreadInitializing: TProcessorThreadInitializing;
// 工作中的线程
FThreads: TList;
// 执行了 terminat 发送退出指令, 正在结束的线程.
FThreadsKilling: TList;
// 最少, 最大线程数
FThreadsMax: Integer;
// 最少, 最大线程数
FThreadsMin: Integer;
// 池平均等待时间
function PoolAverageWaitingTime: Integer;
procedure WriteLog(const Str: string; Level: Integer = 0);
protected
FLastGetPoint: Integer;
// Semaphore，统计任务队列
hSemRequestCount: THandle;
// Waitable timer. 每30触发一次的时间量同步
hTimCheckPoolDown: THandle;
// 线程池停机（检查并清除空闲线程和死线程）
procedure CheckPoolDown;
// 清除死线程，并补充不足的工作线程
procedure CheckThreadsForGrow;
procedure DoProcessed;
procedure DoProcessRequest(aDataObj: TWorkItem; aThread: TProcessorThread);
virtual;
procedure DoQueueEmpty(EmptyKind: TEmptyKind); virtual;
procedure DoThreadFinalizing(aThread: TProcessorThread); virtual;
// 执行事件
procedure DoThreadInitializing(aThread: TProcessorThread); virtual;
// 释放 FThreadsKilling 列表中的线程
procedure FreeFinishedThreads;
// 申请任务
procedure GetRequest(out Request: TWorkItem);
// 清除死线程
procedure KillDeadThreads;
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
// 就进行任务是否重复的检查, 检查发现重复就返回 False
function AddRequest(aDataObject: TWorkItem; CheckForDoubles: Boolean =
False): Boolean; overload;
// 转换枚举类型的线程状态为字串类型
function InfoText: string;
published
// 线程处理任务时触发的事件
property OnProcessRequest: TProcessRequest read FProcessRequest write
FProcessRequest;
// 任务列表为空时解发的事件
property OnQueueEmpty: TQueueEmpty read FQueueEmpty write FQueueEmpty;
// 线程结束时触发的事件
property OnThreadFinalizing: TProcessorThreadFinalizing read
FThreadFinalizing write FThreadFinalizing;
// 线程初始化时触发的事件
property OnThreadInitializing: TProcessorThreadInitializing read
FThreadInitializing write FThreadInitializing;
// 线程超时值（毫秒), 如果处理超时，将视为死线程
property ThreadDeadTimeout: DWORD read FThreadDeadTimeout write
FThreadDeadTimeout default 0;
// 最大线程数
property ThreadsMax: Integer read FThreadsMax write FThreadsMax default 1;
// 最小线程数
property ThreadsMin: Integer read FThreadsMin write FThreadsMin default 0;
end;
type
//日志记志函数
TLogWriteProc = procedure(
const Str: string; //日志
LogID: Integer = 0;
Level: Integer = 0 //Level = 0 - 跟踪信息, 10 - 致命错误
);
var
WriteLog: TLogWriteProc; // 如果存在实例就写日志
implementation
uses
SysUtils;
// 储存请求数据的基本类
{
********************************** TWorkItem ***********************************
}
function TWorkItem.IsTheSame(DataObj: TWorkItem): Boolean;
begin
Result := False;
end; { TWorkItem.IsTheSame }
function TWorkItem.TextForLog: string;
begin
Result := 'Request';
end; { TWorkItem.TextForLog }
{
********************************* TThreadsPool *********************************
}
constructor TThreadsPool.Create(AOwner: TComponent);
var
DueTo: Int64;
begin
{$IFNDEF NOLOGS}
WriteLog('创建线程池', 5);
{$ENDIF}
inherited;
csQueueManagment := TCriticalSection.Create;
FQueue := TList.Create;
csThreadManagment := TCriticalSection.Create;
FThreads := TList.Create;
FThreadsKilling := TList.Create;
FThreadsMin := 0;
FThreadsMax := 1;
FThreadDeadTimeout := 0;
FLastGetPoint := 0;
//
hSemRequestCount := CreateSemaphore(nil, 0, $7FFFFFFF, nil);
DueTo := -1;
//可等待的定时器（只用于Window NT4或更高）
hTimCheckPoolDown := CreateWaitableTimer(nil, False, nil);
if hTimCheckPoolDown = 0 then // Win9x不支持
// In Win9x number of thread will be never decrised
hTimCheckPoolDown := CreateEvent(nil, False, False, nil)
else
SetWaitableTimer(hTimCheckPoolDown, DueTo, 30000, nil, nil, False);
end; { TThreadsPool.Create }
destructor TThreadsPool.Destroy;
var
n, i: Integer;
Handles: array of THandle;
begin
{$IFNDEF NOLOGS}
WriteLog('线程池销毁', 5);
{$ENDIF}
csThreadManagment.Enter;
SetLength(Handles, FThreads.Count);
n := 0;
for i := 0 to FThreads.Count - 1 do
if FThreads[i] <> nil then
begin
Handles[n] := TProcessorThread(FThreads[i]).Handle;
TProcessorThread(FThreads[i]).Terminate;
Inc(n);
end;
csThreadManagment.Leave; // lixiaoyu 添加于 2009.1.6，如没有此行代码无法成功释放正在执行中的工作者线程，死锁。
WaitForMultipleObjects(n, @Handles[0], True, 30000); // 等待工作者线程执行终止 lixiaoyu 注释于 2009.1.6
csThreadManagment.Enter; // lixiaoyu 添加于 2009.1.6 再次进入锁定，并释放资源
for i := 0 to FThreads.Count - 1 do
TProcessorThread(FThreads[i]).Free;
FThreads.Free;
FThreadsKilling.Free;
csThreadManagment.Free;
csQueueManagment.Enter;
for i := FQueue.Count - 1 downto 0 do
TObject(FQueue[i]).Free;
FQueue.Free;
csQueueManagment.Free;
CloseHandle(hSemRequestCount);
CloseHandle(hTimCheckPoolDown);
inherited;
end; { TThreadsPool.Destroy }
function TThreadsPool.AddRequest(aDataObject: TWorkItem; CheckForDoubles:
Boolean = False): Boolean;
var
i: Integer;
begin
{$IFNDEF NOLOGS}
WriteLog('AddRequest(' + aDataObject.TextForLog + ')', 2);
{$ENDIF}
Result := False;
csQueueManagment.Enter;
try
// 如果 CheckForDoubles = TRUE
// 则进行任务是否重复的检查
if CheckForDoubles then
for i := 0 to FQueue.Count - 1 do
if (FQueue[i] <> nil)
and aDataObject.IsTheSame(TWorkItem(FQueue[i])) then
Exit; // 发现有相同的任务
csThreadManagment.Enter;
try
// 清除死线程，并补充不足的工作线程
CheckThreadsForGrow;
// 如果 CheckForDoubles = TRUE
// 则检查是否有相同的任务正在处理中
if CheckForDoubles then
for i := 0 to FThreads.Count - 1 do
if TProcessorThread(FThreads[i]).IamCurrentlyProcess(aDataObject) then
Exit; // 发现有相同的任务
finally
csThreadManagment.Leave;
end;
//将任务加入队列
FQueue.Add(aDataObject);
//释放一个同步信号量
ReleaseSemaphore(hSemRequestCount, 1, nil);
{$IFNDEF NOLOGS}
WriteLog('释放一个同步信号量)', 1);
{$ENDIF}
Result := True;
finally
csQueueManagment.Leave;
end;
{$IFNDEF NOLOGS}
//调试信息
WriteLog('增加一个任务(' + aDataObject.TextForLog + ')', 1);
{$ENDIF}
end; { TThreadsPool.AddRequest }
{
函数名：TThreadsPool.CheckPoolDown
功能描述：线程池停机（检查并清除空闲线程和死线程）
输入参数：无
返回值: 无
创建日期：2006.10.22 11:31
修改日期：2006.
作者：Kook
附加说明：
}
procedure TThreadsPool.CheckPoolDown;
var
i: Integer;
begin
{$IFNDEF NOLOGS}
WriteLog('TThreadsPool.CheckPoolDown', 1);
{$ENDIF}
csThreadManagment.Enter;
try
{$IFNDEF NOLOGS}
WriteLog(InfoText, 2);
{$ENDIF}
// 清除死线程
KillDeadThreads;
// 释放 FThreadsKilling 列表中的线程
FreeFinishedThreads;
// 如果线程空闲，就终止它
for i := FThreads.Count - 1 downto FThreadsMin do
if TProcessorThread(FThreads[i]).isIdle then
begin
//发出终止命令
TProcessorThread(FThreads[i]).Terminate;
//加入待清除队列
FThreadsKilling.Add(FThreads[i]);
//从工作队列中除名
FThreads.Delete(i);
//todo: ？？
Break;
end;
finally
csThreadManagment.Leave;
end;
end; { TThreadsPool.CheckPoolDown }
{
函数名：TThreadsPool.CheckThreadsForGrow
功能描述：清除死线程，并补充不足的工作线程
输入参数：无
返回值: 无
创建日期：2006.10.22 11:31
修改日期：2006.
作者：Kook
附加说明：
}
procedure TThreadsPool.CheckThreadsForGrow;
var
AvgWait: Integer;
i: Integer;
begin
{
New thread created if:
新建线程的条件：
1. 工作线程数小于最小线程数
2. 工作线程数小于最大线程数 and 线程池平均等待时间 < 100ms(系统忙)
3. 任务大于工作线程数的4倍
}
csThreadManagment.Enter;
try
KillDeadThreads;
if FThreads.Count < FThreadsMin then
begin
{$IFNDEF NOLOGS}
WriteLog('工作线程数小于最小线程数', 4);
{$ENDIF}
for i := FThreads.Count to FThreadsMin - 1 do
try
FThreads.Add(TProcessorThread.Create(Self));
except
on e: Exception do
WriteLog(
'TProcessorThread.Create raise: ' + e.ClassName + #13#10#9'Message: '
+ e.Message,
9
);
end
end
else if FThreads.Count < FThreadsMax then
begin
{$IFNDEF NOLOGS}
WriteLog('工作线程数小于最大线程数 and 线程池平均等待时间 < 100ms', 3);
{$ENDIF}
AvgWait := PoolAverageWaitingTime;
{$IFNDEF NOLOGS}
WriteLog(Format(
'FThreads.Count (%d)<FThreadsMax(%d), AvgWait=%d',
[FThreads.Count, FThreadsMax, AvgWait]),
4
);
{$ENDIF}
if AvgWait < 100 then
try
FThreads.Add(TProcessorThread.Create(Self));
except
on e: Exception do
WriteLog(
'TProcessorThread.Create raise: ' + e.ClassName +
#13#10#9'Message: ' + e.Message,
9
);
end;
end;
finally
csThreadManagment.Leave;
end;
end; { TThreadsPool.CheckThreadsForGrow }
procedure TThreadsPool.DoProcessed;
var
i: Integer;
begin
if (FLastGetPoint < FQueue.Count) then
Exit;
csThreadManagment.Enter;
try
for i := 0 to FThreads.Count - 1 do
if TProcessorThread(FThreads[i]).FCurState in [tcsProcessing] then
Exit;
finally
csThreadManagment.Leave;
end;
DoQueueEmpty(ekProcessingFinished);
end; { TThreadsPool.DoProcessed }
procedure TThreadsPool.DoProcessRequest(aDataObj: TWorkItem; aThread:
TProcessorThread);
begin
if Assigned(FProcessRequest) then
FProcessRequest(Self, aDataObj, aThread);
end; { TThreadsPool.DoProcessRequest }
procedure TThreadsPool.DoQueueEmpty(EmptyKind: TEmptyKind);
begin
if Assigned(FQueueEmpty) then
FQueueEmpty(Self, EmptyKind);
end; { TThreadsPool.DoQueueEmpty }
procedure TThreadsPool.DoThreadFinalizing(aThread: TProcessorThread);
begin
if Assigned(FThreadFinalizing) then
FThreadFinalizing(Self, aThread);
end; { TThreadsPool.DoThreadFinalizing }
procedure TThreadsPool.DoThreadInitializing(aThread: TProcessorThread);
begin
if Assigned(FThreadInitializing) then
FThreadInitializing(Self, aThread);
end; { TThreadsPool.DoThreadInitializing }
{
函数名：TThreadsPool.FreeFinishedThreads
功能描述：释放 FThreadsKilling 列表中的线程
输入参数：无
返回值: 无
创建日期：2006.10.22 11:34
修改日期：2006.
作者：Kook
附加说明：
}
procedure TThreadsPool.FreeFinishedThreads;
var
i: Integer;
begin
if csThreadManagment.TryEnter then
try
for i := FThreadsKilling.Count - 1 downto 0 do
if TProcessorThread(FThreadsKilling[i]).isFinished then
begin
TProcessorThread(FThreadsKilling[i]).Free;
FThreadsKilling.Delete(i);
end;
finally
csThreadManagment.Leave
end;
end; { TThreadsPool.FreeFinishedThreads }
{
函数名：TThreadsPool.GetRequest
功能描述：申请任务
输入参数：out Request: TRequestDataObject
返回值: 无
创建日期：2006.10.22 11:34
修改日期：2006.
作者：Kook
附加说明：
}
procedure TThreadsPool.GetRequest(out Request: TWorkItem);
begin
{$IFNDEF NOLOGS}
WriteLog('申请任务', 2);
{$ENDIF}
csQueueManagment.Enter;
try
//跳过空的队列元素
while (FLastGetPoint < FQueue.Count) and (FQueue[FLastGetPoint] = nil) do
Inc(FLastGetPoint);
Assert(FLastGetPoint < FQueue.Count);
//压缩队列，清除空元素
if (FQueue.Count > 127) and (FLastGetPoint >= (3 * FQueue.Count) div 4) then
begin
{$IFNDEF NOLOGS}
WriteLog('FQueue.Pack', 1);
{$ENDIF}
FQueue.Pack;
FLastGetPoint := 0;
end;
Request := TWorkItem(FQueue[FLastGetPoint]);
FQueue[FLastGetPoint] := nil;
inc(FLastGetPoint);
if (FLastGetPoint = FQueue.Count) then //如果队列中无任务
begin
DoQueueEmpty(ekQueueEmpty);
FQueue.Clear;
FLastGetPoint := 0;
end;
finally
csQueueManagment.Leave;
end;
end; { TThreadsPool.GetRequest }
function TThreadsPool.InfoText: string;
begin
Result := '';
//end;
//{$ELSE}
//var
// i: Integer;
//begin
// csQueueManagment.Enter;
// csThreadManagment.Enter;
// try
// if (FThreads.Count = 0) and (FThreadsKilling.Count = 1) and
// TProcessorThread(FThreadsKilling[0]).isFinished then
// FreeFinishedThreads;
//
// Result := Format(
// 'Pool thread: Min=%d, Max=%d, WorkingThreadsCount=%d, TerminatedThreadCount=%d, QueueLength=%d'#13#10,
// [ThreadsMin, ThreadsMax, FThreads.Count, FThreadsKilling.Count,
// FQueue.Count]
// );
// if FThreads.Count > 0 then
// Result := Result + 'Working threads:'#13#10;
// for i := 0 to FThreads.Count - 1 do
// Result := Result + TProcessorThread(FThreads[i]).InfoText + #13#10;
// if FThreadsKilling.Count > 0 then
// Result := Result + 'Terminated threads:'#13#10;
// for i := 0 to FThreadsKilling.Count - 1 do
// Result := Result + TProcessorThread(FThreadsKilling[i]).InfoText + #13#10;
// finally
// csThreadManagment.Leave;
// csQueueManagment.Leave;
// end;
//end;
//{$ENDIF}
end; { TThreadsPool.InfoText }
{
函数名：TThreadsPool.KillDeadThreads
功能描述：清除死线程
输入参数：无
返回值: 无
创建日期：2006.10.22 11:32
修改日期：2006.
作者：Kook
附加说明：
}
procedure TThreadsPool.KillDeadThreads;
var
i: Integer;
begin
// Check for dead threads
if csThreadManagment.TryEnter then
try
for i := 0 to FThreads.Count - 1 do
if TProcessorThread(FThreads[i]).IsDead then
begin
// Dead thread moverd to other list.
// New thread created to replace dead one
TProcessorThread(FThreads[i]).Terminate;
FThreadsKilling.Add(FThreads[i]);
try
FThreads[i] := TProcessorThread.Create(Self);
except
on e: Exception do
begin
FThreads[i] := nil;
{$IFNDEF NOLOGS}
WriteLog(
'TProcessorThread.Create raise: ' + e.ClassName +
#13#10#9'Message: ' + e.Message,
9
);
{$ENDIF}
end;
end;
end;
finally
csThreadManagment.Leave
end;
end; { TThreadsPool.KillDeadThreads }
function TThreadsPool.PoolAverageWaitingTime: Integer;
var
i: Integer;
begin
Result := 0;
if FThreads.Count > 0 then
begin
for i := 0 to FThreads.Count - 1 do
Inc(result, TProcessorThread(FThreads[i]).AverageWaitingTime);
Result := Result div FThreads.Count
end
else
Result := 1;
end; { TThreadsPool.PoolAverageWaitingTime }
procedure TThreadsPool.WriteLog(const Str: string; Level: Integer = 0);
begin
{$IFNDEF NOLOGS}
uThreadPool.WriteLog(Str, 0, Level);
{$ENDIF}
end; { TThreadsPool.WriteLog }
// 工作线程仅用于线程池内，不要直接创建并调用它。
{
******************************* TProcessorThread *******************************
}
constructor TProcessorThread.Create(APool: TThreadsPool);
begin
WriteLog('创建工作线程', 5);
inherited Create(True);
FPool := aPool;
FAverageWaitingTime := 1000;
FAverageProcessing := 3000;
sInitError := '';
{
各参数的意义如下：
　
参数一：填上 nil 即可。
参数二：是否采用手动调整灯号。
参数三：灯号的起始状态，False 表示红灯。
参数四：Event 名称, 对象名称相同的话，会指向同一个对象，所以想要有两个Event对象，便要有两个不同的名称(这名称以字符串来存.为NIL的话系统每次会自己创建一个不同的名字，就是被次创建的都是新的EVENT)。
传回值：Event handle。
}
hInitFinished := CreateEvent(nil, True, False, nil);
hThreadTerminated := CreateEvent(nil, True, False, nil);
csProcessingDataObject := TCriticalSection.Create;
try
WriteLog('TProcessorThread.Create::Resume', 3);
Resume;
//阻塞, 等待初始化完成
WaitForSingleObject(hInitFinished, INFINITE);
if sInitError <> '' then
raise Exception.Create(sInitError);
finally
CloseHandle(hInitFinished);
end;
WriteLog('TProcessorThread.Create::Finished', 3);
end; { TProcessorThread.Create }
destructor TProcessorThread.Destroy;
begin
WriteLog('工作线程销毁', 5);
CloseHandle(hThreadTerminated);
csProcessingDataObject.Free;
inherited;
end; { TProcessorThread.Destroy }
function TProcessorThread.AverageProcessingTime: DWORD;
begin
if (FCurState in [tcsProcessing]) then
Result := NewAverage(FAverageProcessing, GetTickCount - uProcessingStart)
else
Result := FAverageProcessing
end; { TProcessorThread.AverageProcessingTime }
function TProcessorThread.AverageWaitingTime: DWORD;
begin
if (FCurState in [tcsWaiting, tcsCheckingDown]) then
Result := NewAverage(FAverageWaitingTime, GetTickCount - uWaitingStart)
else
Result := FAverageWaitingTime
end; { TProcessorThread.AverageWaitingTime }
procedure TProcessorThread.Execute;
type
THandleID = (hidTerminateThread, hidRequest, hidCheckPoolDown);
var
WaitedTime: Integer;
Handles: array[THandleID] of THandle;
begin
WriteLog('工作线程进常运行', 3);
//当前状态：初始化
FCurState := tcsInitializing;
try
//执行外部事件
FPool.DoThreadInitializing(Self);
except
on e: Exception do
sInitError := e.Message;
end;
//初始化完成，初始化Event绿灯
SetEvent(hInitFinished);
WriteLog('TProcessorThread.Execute::Initialized', 3);
//引用线程池的同步 Event
Handles[hidTerminateThread] := hThreadTerminated;
Handles[hidRequest] := FPool.hSemRequestCount;
Handles[hidCheckPoolDown] := FPool.hTimCheckPoolDown;
//时间戳，
//todo: 好像在线程中用 GetTickCount; 会不正常
uWaitingStart := GetTickCount;
//任务置空
FProcessingDataObject := nil;
//大巡环
while not terminated do
begin
//当前状态：等待
FCurState := tcsWaiting;
//阻塞线程，使线程休眠
case WaitForMultipleObjects(Length(Handles), @Handles, False, INFINITE) -
WAIT_OBJECT_0 of
WAIT_OBJECT_0 + ord(hidTerminateThread):
begin
WriteLog('TProcessorThread.Execute:: Terminate event signaled ', 5);
//当前状态：正在终止线程
FCurState := tcsTerminating;
//退出大巡环(结束线程)
Break;
end;
WAIT_OBJECT_0 + ord(hidRequest):
begin
WriteLog('TProcessorThread.Execute:: Request semaphore signaled ', 3);
//等待的时间
WaitedTime := GetTickCount - uWaitingStart;
//重新计算平均等待时间
FAverageWaitingTime := NewAverage(FAverageWaitingTime, WaitedTime);
//当前状态：申请任务
FCurState := tcsGetting;
//如果等待时间过短，则检查工作线程是否足够
if WaitedTime < 5 then
FPool.CheckThreadsForGrow;
//从线程池的任务队列中得到任务
FPool.GetRequest(FProcessingDataObject);
//开始处理的时间戳
uProcessingStart := GetTickCount;
//当前状态：执行任务
FCurState := tcsProcessing;
try
{$IFNDEF NOLOGS}
WriteLog('Processing: ' + FProcessingDataObject.TextForLog, 2);
{$ENDIF}
//执行任务
FPool.DoProcessRequest(FProcessingDataObject, Self);
except
on e: Exception do
WriteLog(
'OnProcessRequest for ' + FProcessingDataObject.TextForLog +
#13#10'raise Exception: ' + e.Message,
8
);
end;
//释放任务对象
csProcessingDataObject.Enter;
try
FProcessingDataObject.Free;
FProcessingDataObject := nil;
finally
csProcessingDataObject.Leave;
end;
//重新计算
FAverageProcessing := NewAverage(FAverageProcessing, GetTickCount -
uProcessingStart);
//当前状态：执行任务完毕
FCurState := tcsProcessed;
//执行线程外事件
FPool.DoProcessed;
uWaitingStart := GetTickCount;
end;
WAIT_OBJECT_0 + ord(hidCheckPoolDown):
begin
// !!! Never called under Win9x
WriteLog('TProcessorThread.Execute:: CheckPoolDown timer signaled ',
4);
//当前状态：线程池停机（检查并清除空闲线程和死线程）
FCurState := tcsCheckingDown;
FPool.CheckPoolDown;
end;
end;
end;
FCurState := tcsTerminating;
FPool.DoThreadFinalizing(Self);
end; { TProcessorThread.Execute }
function TProcessorThread.IamCurrentlyProcess(DataObj: TWorkItem): Boolean;
begin
csProcessingDataObject.Enter;
try
Result := (FProcessingDataObject <> nil) and
DataObj.IsTheSame(FProcessingDataObject);
finally
csProcessingDataObject.Leave;
end;
end; { TProcessorThread.IamCurrentlyProcess }
function TProcessorThread.InfoText: string;
const
ThreadStateNames: array[TThreadState] of string =
(
'tcsInitializing',
'tcsWaiting',
'tcsGetting',
'tcsProcessing',
'tcsProcessed',
'tcsTerminating',
'tcsCheckingDown'
);
begin
{$IFNDEF NOLOGS}
Result := Format(
'%5d: %15s, AverageWaitingTime=%6d, AverageProcessingTime=%6d',
[ThreadID, ThreadStateNames[FCurState], AverageWaitingTime,
AverageProcessingTime]
);
case FCurState of
tcsWaiting:
Result := Result + ', WaitingTime=' + IntToStr(GetTickCount -
uWaitingStart);
tcsProcessing:
Result := Result + ', ProcessingTime=' + IntToStr(GetTickCount -
uProcessingStart);
end;
csProcessingDataObject.Enter;
try
if FProcessingDataObject <> nil then
Result := Result + ' ' + FProcessingDataObject.TextForLog;
finally
csProcessingDataObject.Leave;
end;
{$ENDIF}
end; { TProcessorThread.InfoText }
function TProcessorThread.IsDead: Boolean;
begin
Result :=
Terminated or
(FPool.ThreadDeadTimeout > 0) and (FCurState = tcsProcessing) and
(GetTickCount - uProcessingStart > FPool.ThreadDeadTimeout);
if Result then
WriteLog('Thread dead', 5);
end; { TProcessorThread.IsDead }
function TProcessorThread.isFinished: Boolean;
begin
Result := WaitForSingleObject(Handle, 0) = WAIT_OBJECT_0;
end; { TProcessorThread.isFinished }
function TProcessorThread.isIdle: Boolean;
begin
// 如果线程状态是 tcsWaiting, tcsCheckingDown
// 并且空间时间 > 100ms,
// 并且平均等候任务时间大于平均工作时间的 50%
// 则视为空闲。
Result :=
(FCurState in [tcsWaiting, tcsCheckingDown]) and
(AverageWaitingTime > 100) and
(AverageWaitingTime * 2 > AverageProcessingTime);
end; { TProcessorThread.isIdle }
function TProcessorThread.NewAverage(OldAvg, NewVal: Integer): Integer;
begin
Result := (OldAvg * 2 + NewVal) div 3;
end; { TProcessorThread.NewAverage }
procedure TProcessorThread.Terminate;
begin
WriteLog('TProcessorThread.Terminate', 5);
inherited Terminate;
SetEvent(hThreadTerminated);
end; { TProcessorThread.Terminate }
procedure TProcessorThread.WriteLog(const Str: string; Level: Integer = 0);
begin
{$IFNDEF NOLOGS}
uThreadPool.WriteLog(Str, ThreadID, Level);
{$ENDIF}
end; { TProcessorThread.WriteLog }
{
******************************* TCriticalSection *******************************
}
constructor TCriticalSection.Create;
begin
InitializeCriticalSection(FSection);
end; { TCriticalSection.Create }
destructor TCriticalSection.Destroy;
begin
DeleteCriticalSection(FSection);
end; { TCriticalSection.Destroy }
procedure TCriticalSection.Enter;
begin
EnterCriticalSection(FSection);
end; { TCriticalSection.Enter }
procedure TCriticalSection.Leave;
begin
LeaveCriticalSection(FSection);
end; { TCriticalSection.Leave }
function TCriticalSection.TryEnter: Boolean;
begin
Result := TryEnterCriticalSection(FSection);
end; { TCriticalSection.TryEnter }
procedure NoLogs(const Str: string; LogID: Integer = 0; Level: Integer = 0);
begin
end;
initialization
WriteLog := NoLogs;
end.

复制代码

使用方法

// 创建线程池
FThreadPool := TThreadsPool.Create(Self); // 创建线程池
FThreadPool.ThreadsMin := 5; // 初始工作线程数
FThreadPool.ThreadsMax := 50; // 最大允许工作线程数
FThreadPool.OnProcessRequest := DealwithCommRecvData; // 线程工作函数(DealwithCommRecvData在工作者线程的Execute方法中被调用)
// 使用线程池
var
　AWorkItem: TRecvCommDataWorkItem; // 继承自TWorkItem
begin
　AWorkItem := TRecvCommDataWorkItem.Create;
　Move(PData[0], AWorkItem.FRecvData[0], PDataLen);
　AWorkItem.FRecvDataLen := PDataLen;
　FThreadPool.AddRequest(AWorkItem); // 向线程池分配一个任务
end;

复制代码

source:http://blog.csdn.net/babyvspp/archive/2008/01/01/2008234.aspx
source:http://www.delphifans.com/SoftView/SoftView_2722.html

本主题由皇帝 5207 于 2009-7-3 22:59:21 执行主题分类操作

相信与不相信都是矛盾的. 5207宣!
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