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)
private
// 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)
private
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);
{$ENDIF}
csThreadManagment.Enter;
SetLength(Handles, FThreads.Count);
n := 0;
for i := 0 to FThreads.Count - 1 do
if FThreads[i] <> nil then
begin
Handles[n] := TProcessorThread(FThreads[i]).Handle;
TProcessorThread(FThreads[i]).Terminate;
Inc(n);
end;
WaitForMultipleObjects(n, @Handles[0], True, 30000);
for i := 0 to FThreads.Count - 1 do
TProcessorThread(FThreads[i]).Free;
FThreads.Free;
FThreadsKilling.Free;
csThreadManagment.Free;
csQueueManagment.Enter;
for i := FQueue.Count - 1 downto 0 do
TObject(FQueue[i]).Free;
FQueue.Free;
csQueueManagment.Free;
CloseHandle(hSemRequestCount);
CloseHandle(hTimCheckPoolDown);
inherited;
end; { TThreadsPool.Destroy }
function TThreadsPool.AddRequest(aDataObject: TWorkItem; CheckForDoubles:
Boolean = False): Boolean;
var
i: Integer;
begin
{$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 }
