src/DiskIO/IpcIo/IpcIoFile.h

   1 /*
   2  * Copyright (C) 1996-2015 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #ifndef SQUID_IPC_IOFILE_H
  10 #define SQUID_IPC_IOFILE_H
  11
  12 #include "base/AsyncCall.h"
  13 #include "cbdata.h"
  14 #include "DiskIO/DiskFile.h"
  15 #include "DiskIO/IORequestor.h"
  16 #include "ipc/forward.h"
  17 #include "ipc/mem/Page.h"
  18 #include "SquidString.h"
  19 #include <list>
  20 #include <map>
  21 #include <memory>
  22
  23 namespace Ipc
  24 {
  25 class FewToFewBiQueue;
  26 } // Ipc
  27
  28 // TODO: expand to all classes
  29 namespace IpcIo
  30 {
  31
  32 /// what kind of I/O the disker needs to do or have done
  33 typedef enum { cmdNone, cmdOpen, cmdRead, cmdWrite } Command;
  34
  35 } // namespace IpcIo
  36
  37 /// converts DiskIO requests to IPC queue messages
  38 class IpcIoMsg
  39 {
  40 public:
  41     IpcIoMsg();
  42
  43 public:
  44     unsigned int requestId; ///< unique for requestor; matches request w/ response
  45
  46     off_t offset;
  47     size_t len;
  48     Ipc::Mem::PageId page;
  49
  50     IpcIo::Command command; ///< what disker is supposed to do or did
  51     struct timeval start; ///< when the I/O request was converted to IpcIoMsg
  52
  53     int xerrno; ///< I/O error code or zero
  54 };
  55
  56 class IpcIoPendingRequest;
  57
  58 class IpcIoFile: public DiskFile
  59 {
  60     CBDATA_CLASS(IpcIoFile);
  61
  62 public:
  63     typedef RefCount<IpcIoFile> Pointer;
  64
  65     IpcIoFile(char const *aDb);
  66     virtual ~IpcIoFile();
  67
  68     /* DiskFile API */
  69     virtual void configure(const Config &cfg);
  70     virtual void open(int flags, mode_t mode, RefCount<IORequestor> callback);
  71     virtual void create(int flags, mode_t mode, RefCount<IORequestor> callback);
  72     virtual void read(ReadRequest *);
  73     virtual void write(WriteRequest *);
  74     virtual void close();
  75     virtual bool error() const;
  76     virtual int getFD() const;
  77     virtual bool canRead() const;
  78     virtual bool canWrite() const;
  79     virtual bool ioInProgress() const;
  80
  81     /// handle open response from coordinator
  82     static void HandleOpenResponse(const Ipc::StrandSearchResponse &response);
  83
  84     /// handle queue push notifications from worker or disker
  85     static void HandleNotification(const Ipc::TypedMsgHdr &msg);
  86
  87     DiskFile::Config config; ///< supported configuration options
  88
  89 protected:
  90     friend class IpcIoPendingRequest;
  91     void openCompleted(const Ipc::StrandSearchResponse *const response);
  92     void readCompleted(ReadRequest *readRequest, IpcIoMsg *const response);
  93     void writeCompleted(WriteRequest *writeRequest, const IpcIoMsg *const response);
  94     bool canWait() const;
  95
  96 private:
  97     void trackPendingRequest(const unsigned int id, IpcIoPendingRequest *const pending);
  98     void push(IpcIoPendingRequest *const pending);
  99     IpcIoPendingRequest *dequeueRequest(const unsigned int requestId);
 100
 101     static void Notify(const int peerId);
 102
 103     static void OpenTimeout(void *const param);
 104     static void CheckTimeouts(void *const param);
 105     void checkTimeouts();
 106     void scheduleTimeoutCheck();
 107
 108     static void HandleResponses(const char *const when);
 109     void handleResponse(IpcIoMsg &ipcIo);
 110
 111     static void DiskerHandleMoreRequests(void*);
 112     static void DiskerHandleRequests();
 113     static void DiskerHandleRequest(const int workerId, IpcIoMsg &ipcIo);
 114     static bool WaitBeforePop();
 115
 116 private:
 117     const String dbName; ///< the name of the file we are managing
 118     int diskId; ///< the process ID of the disker we talk to
 119     RefCount<IORequestor> ioRequestor;
 120
 121     bool error_; ///< whether we have seen at least one I/O error (XXX)
 122
 123     unsigned int lastRequestId; ///< last requestId used
 124
 125     /// maps requestId to the handleResponse callback
 126     typedef std::map<unsigned int, IpcIoPendingRequest*> RequestMap;
 127     RequestMap requestMap1; ///< older (or newer) pending requests
 128     RequestMap requestMap2; ///< newer (or older) pending requests
 129     RequestMap *olderRequests; ///< older requests (map1 or map2)
 130     RequestMap *newerRequests; ///< newer requests (map2 or map1)
 131     bool timeoutCheckScheduled; ///< we expect a CheckTimeouts() call
 132
 133     static const double Timeout; ///< timeout value in seconds
 134
 135     typedef std::list<Pointer> IpcIoFileList;
 136     static IpcIoFileList WaitingForOpen; ///< pending open requests
 137
 138     ///< maps diskerId to IpcIoFile, cleared in destructor
 139     typedef std::map<int, IpcIoFile*> IpcIoFilesMap;
 140     static IpcIoFilesMap IpcIoFiles;
 141
 142     typedef Ipc::FewToFewBiQueue Queue;
 143     static std::auto_ptr<Queue> queue; ///< IPC queue
 144
 145     /// whether we are waiting for an event to handle still queued I/O requests
 146     static bool DiskerHandleMoreRequestsScheduled;
 147 };
 148
 149 /// keeps original I/O request parameters while disker is handling the request
 150 class IpcIoPendingRequest
 151 {
 152 public:
 153     IpcIoPendingRequest(const IpcIoFile::Pointer &aFile);
 154
 155     /// called when response is received and, with a nil response, on timeouts
 156     void completeIo(IpcIoMsg *const response);
 157
 158 public:
 159     const IpcIoFile::Pointer file; ///< the file object waiting for the response
 160     ReadRequest *readRequest; ///< set if this is a read requests
 161     WriteRequest *writeRequest; ///< set if this is a write request
 162
 163 private:
 164     IpcIoPendingRequest(const IpcIoPendingRequest &d); // not implemented
 165     IpcIoPendingRequest &operator =(const IpcIoPendingRequest &d); // ditto
 166 };
 167
 168 #endif /* SQUID_IPC_IOFILE_H */
 169