src/DiskIO/IpcIo/IpcIoFile.h

   1 #ifndef SQUID_IPC_IOFILE_H
   2 #define SQUID_IPC_IOFILE_H
   3
   4 #include "base/AsyncCall.h"
   5 #include "cbdata.h"
   6 #include "DiskIO/DiskFile.h"
   7 #include "DiskIO/IORequestor.h"
   8 #include "ipc/forward.h"
   9 #include <map>
  10
  11 // TODO: expand to all classes
  12 namespace IpcIo {
  13
  14 /// what kind of I/O the disker needs to do or have done
  15 typedef enum { cmdNone, cmdOpen, cmdRead, cmdWrite } Command;
  16
  17 enum { BufCapacity = 32*1024 }; // XXX: must not exceed TypedMsgHdr.maxSize
  18
  19 } // namespace IpcIo
  20
  21
  22 /// converts DiskIO requests to IPC messages
  23 // TODO: make this IpcIoMsg to make IpcIoRequest and IpcIoResponse similar
  24 class IpcIoRequest {
  25 public:
  26     IpcIoRequest();
  27
  28     explicit IpcIoRequest(const Ipc::TypedMsgHdr& msg); ///< from recvmsg()
  29     void pack(Ipc::TypedMsgHdr& msg) const; ///< prepare for sendmsg()
  30
  31 public:
  32     int requestorId; ///< kidId of the requestor; used for response destination
  33     unsigned int requestId; ///< unique for sender; matches request w/ response
  34
  35     /* ReadRequest and WriteRequest parameters to pass to disker */
  36     char buf[IpcIo::BufCapacity]; // XXX: inefficient
  37     off_t offset;
  38     size_t len;
  39
  40     IpcIo::Command command; ///< what disker is supposed to do
  41 };
  42
  43 /// disker response to IpcIoRequest
  44 class IpcIoResponse {
  45 public:
  46     IpcIoResponse();
  47
  48     explicit IpcIoResponse(const Ipc::TypedMsgHdr& msg); ///< from recvmsg()
  49     void pack(Ipc::TypedMsgHdr& msg) const; ///< prepare for sendmsg()
  50
  51 public:
  52     int diskId; ///< kidId of the responding disker
  53     unsigned int requestId; ///< unique for sender; matches request w/ response
  54
  55     char buf[IpcIo::BufCapacity]; // XXX: inefficient
  56     size_t len;
  57
  58     IpcIo::Command command; ///< what disker did
  59
  60     int xerrno; ///< I/O error code or zero
  61 };
  62
  63 class IpcIoPendingRequest;
  64
  65 class IpcIoFile: public DiskFile
  66 {
  67
  68 public:
  69     typedef RefCount<IpcIoFile> Pointer;
  70
  71     IpcIoFile(char const *aDb);
  72     virtual ~IpcIoFile();
  73
  74     /* DiskFile API */
  75     virtual void open(int flags, mode_t mode, RefCount<IORequestor> callback);
  76     virtual void create(int flags, mode_t mode, RefCount<IORequestor> callback);
  77     virtual void read(ReadRequest *);
  78     virtual void write(WriteRequest *);
  79     virtual void close();
  80     virtual bool error() const;
  81     virtual int getFD() const;
  82     virtual bool canRead() const;
  83     virtual bool canWrite() const;
  84     virtual bool ioInProgress() const;
  85
  86     /// finds and calls the right IpcIoFile upon disker's response
  87     static void HandleResponse(const Ipc::TypedMsgHdr &response);
  88
  89     /// disker entry point for remote I/O requests
  90     static void HandleRequest(const IpcIoRequest &request);
  91
  92 private:
  93     void send(IpcIoRequest &request, IpcIoPendingRequest *pending);
  94
  95     void openCompleted(const IpcIoResponse &);
  96     void readCompleted(ReadRequest *readRequest, const IpcIoResponse &);
  97     void writeCompleted(WriteRequest *writeRequest, const IpcIoResponse &);
  98
  99     static void RequestTimedOut(void* param);
 100     void requestTimedOut();
 101     void removeTimeoutEvent();
 102     static IpcIoPendingRequest *DequeueRequest(unsigned int requestId);
 103
 104 private:
 105     const String dbName; ///< the name of the file we are managing
 106     int diskId; ///< the process ID of the disker we talk to
 107     RefCount<IORequestor> ioRequestor;
 108
 109     int ioLevel; ///< number of pending I/O requests using this file
 110
 111     bool error_; ///< whether we have seen at least one I/O error (XXX)
 112
 113     /// maps requestId to the handleResponse callback
 114     typedef std::map<unsigned int, IpcIoPendingRequest*> RequestsMap;
 115     static RequestsMap TheRequestsMap; ///< pending requests map
 116
 117     static unsigned int LastRequestId; ///< last requestId used
 118
 119     CBDATA_CLASS2(IpcIoFile);
 120 };
 121
 122
 123 /// keeps original I/O request parameters while disker is handling the request
 124 class IpcIoPendingRequest
 125 {
 126 public:
 127     IpcIoPendingRequest(const IpcIoFile::Pointer &aFile);
 128
 129 public:
 130     IpcIoFile::Pointer file; ///< the file object waiting for the response
 131     ReadRequest *readRequest; ///< set if this is a read requests
 132     WriteRequest *writeRequest; ///< set if this is a write request
 133
 134 private:
 135     IpcIoPendingRequest(const IpcIoPendingRequest &d); // not implemented
 136     IpcIoPendingRequest &operator =(const IpcIoPendingRequest &d); // ditto
 137 };
 138
 139
 140 #endif /* SQUID_IPC_IOFILE_H */