tclIO.h Go to the documentation of this file. /* * tclIO.h -- * * This file provides the generic portions (those that are the same on * all platforms and for all channel types) of Tcl's IO facilities. * * Copyright (c) 1998-2000 Ajuba Solutions * Copyright (c) 1995-1997 Sun Microsystems, Inc. * * See the file "license.terms" for information on usage and redistribution of * this file, and for a DISCLAIMER OF ALL WARRANTIES. * * RCS: @(#) $Id: tclIO.h,v 1.11 2007/12/13 15:23:18 dgp Exp $ */ /* * Make sure that both EAGAIN and EWOULDBLOCK are defined. This does not * compile on systems where neither is defined. We want both defined so that * we can test safely for both. In the code we still have to test for both * because there may be systems on which both are defined and have different * values. */ #if ((!defined(EWOULDBLOCK)) && (defined(EAGAIN))) # define EWOULDBLOCK EAGAIN #endif #if ((!defined(EAGAIN)) && (defined(EWOULDBLOCK))) # define EAGAIN EWOULDBLOCK #endif #if ((!defined(EAGAIN)) && (!defined(EWOULDBLOCK))) #error one of EWOULDBLOCK or EAGAIN must be defined #endif /* * The following structure encapsulates the state for a background channel * copy. Note that the data buffer for the copy will be appended to this * structure. */ typedef struct CopyState { struct Channel *readPtr; /* Pointer to input channel. */ struct Channel *writePtr; /* Pointer to output channel. */ int readFlags; /* Original read channel flags. */ int writeFlags; /* Original write channel flags. */ int toRead; /* Number of bytes to copy, or -1. */ int total; /* Total bytes transferred (written). */ Tcl_Interp *interp; /* Interp that started the copy. */ Tcl_Obj *cmdPtr; /* Command to be invoked at completion. */ int bufSize; /* Size of appended buffer. */ char buffer[1]; /* Copy buffer, this must be the last * field. */ } CopyState; /* * struct ChannelBuffer: * * Buffers data being sent to or from a channel. */ typedef struct ChannelBuffer { int nextAdded; /* The next position into which a character * will be put in the buffer. */ int nextRemoved; /* Position of next byte to be removed from * the buffer. */ int bufLength; /* How big is the buffer? */ struct ChannelBuffer *nextPtr; /* Next buffer in chain. */ char buf[4]; /* Placeholder for real buffer. The real * buffer occuppies this space + bufSize-4 * bytes. This must be the last field in the * structure. */ } ChannelBuffer; #define CHANNELBUFFER_HEADER_SIZE (sizeof(ChannelBuffer) - 4) /* * How much extra space to allocate in buffer to hold bytes from previous * buffer (when converting to UTF-8) or to hold bytes that will go to next * buffer (when converting from UTF-8). */ #define BUFFER_PADDING 16 /* * The following defines the *default* buffer size for channels. */ #define CHANNELBUFFER_DEFAULT_SIZE (1024 * 4) /* * Structure to record a close callback. One such record exists for each close * callback registered for a channel. */ typedef struct CloseCallback { Tcl_CloseProc *proc; /* The procedure to call. */ ClientData clientData; /* Arbitrary one-word data to pass to the * callback. */ struct CloseCallback *nextPtr; /* For chaining close callbacks. */ } CloseCallback; /* * The following structure describes the information saved from a call to * "fileevent". This is used later when the event being waited for to invoke * the saved script in the interpreter designed in this record. */ typedef struct EventScriptRecord { struct Channel *chanPtr; /* The channel for which this script is * registered. This is used only when an error * occurs during evaluation of the script, to * delete the handler. */ Tcl_Obj *scriptPtr; /* Script to invoke. */ Tcl_Interp *interp; /* In what interpreter to invoke script? */ int mask; /* Events must overlap current mask for the * stored script to be invoked. */ struct EventScriptRecord *nextPtr; /* Next in chain of records. */ } EventScriptRecord; /* * struct Channel: * * One of these structures is allocated for each open channel. It contains * data specific to the channel but which belongs to the generic part of the * Tcl channel mechanism, and it points at an instance specific (and type * specific) instance data, and at a channel type structure. */ typedef struct Channel { struct ChannelState *state; /* Split out state information */ ClientData instanceData; /* Instance-specific data provided by creator * of channel. */ Tcl_ChannelType *typePtr; /* Pointer to channel type structure. */ struct Channel *downChanPtr;/* Refers to channel this one was stacked * upon. This reference is NULL for normal * channels. See Tcl_StackChannel. */ struct Channel *upChanPtr; /* Refers to the channel above stacked this * one. NULL for the top most channel. */ /* * Intermediate buffers to hold pre-read data for consumption by a newly * stacked transformation. See 'Tcl_StackChannel'. */ ChannelBuffer *inQueueHead; /* Points at first buffer in input queue. */ ChannelBuffer *inQueueTail; /* Points at last buffer in input queue. */ } Channel; /* * struct ChannelState: * * One of these structures is allocated for each open channel. It contains * data specific to the channel but which belongs to the generic part of the * Tcl channel mechanism, and it points at an instance specific (and type * specific) instance data, and at a channel type structure. */ typedef struct ChannelState { CONST char *channelName; /* The name of the channel instance in Tcl * commands. Storage is owned by the generic * IO code, is dynamically allocated. */ int flags; /* ORed combination of the flags defined * below. */ Tcl_Encoding encoding; /* Encoding to apply when reading or writing * data on this channel. NULL means no * encoding is applied to data. */ Tcl_EncodingState inputEncodingState; /* Current encoding state, used when * converting input data bytes to UTF-8. */ int inputEncodingFlags; /* Encoding flags to pass to conversion * routine when converting input data bytes to * UTF-8. May be TCL_ENCODING_START before * converting first byte and TCL_ENCODING_END * when EOF is seen. */ Tcl_EncodingState outputEncodingState; /* Current encoding state, used when * converting UTF-8 to output data bytes. */ int outputEncodingFlags; /* Encoding flags to pass to conversion * routine when converting UTF-8 to output * data bytes. May be TCL_ENCODING_START * before converting first byte and * TCL_ENCODING_END when EOF is seen. */ TclEolTranslation inputTranslation; /* What translation to apply for end of line * sequences on input? */ TclEolTranslation outputTranslation; /* What translation to use for generating end * of line sequences in output? */ int inEofChar; /* If nonzero, use this as a signal of EOF on * input. */ int outEofChar; /* If nonzero, append this to the channel when * it is closed if it is open for writing. */ int unreportedError; /* Non-zero if an error report was deferred * because it happened in the background. The * value is the POSIX error code. */ int refCount; /* How many interpreters hold references to * this IO channel? */ CloseCallback *closeCbPtr; /* Callbacks registered to be called when the * channel is closed. */ char *outputStage; /* Temporary staging buffer used when * translating EOL before converting from * UTF-8 to external form. */ ChannelBuffer *curOutPtr; /* Current output buffer being filled. */ ChannelBuffer *outQueueHead;/* Points at first buffer in output queue. */ ChannelBuffer *outQueueTail;/* Points at last buffer in output queue. */ ChannelBuffer *saveInBufPtr;/* Buffer saved for input queue - eliminates * need to allocate a new buffer for "gets" * that crosses buffer boundaries. */ ChannelBuffer *inQueueHead; /* Points at first buffer in input queue. */ ChannelBuffer *inQueueTail; /* Points at last buffer in input queue. */ struct ChannelHandler *chPtr;/* List of channel handlers registered for * this channel. */ int interestMask; /* Mask of all events this channel has * handlers for. */ EventScriptRecord *scriptRecordPtr; /* Chain of all scripts registered for event * handlers ("fileevent") on this channel. */ int bufSize; /* What size buffers to allocate? */ Tcl_TimerToken timer; /* Handle to wakeup timer for this channel. */ CopyState *csPtr; /* State of background copy, or NULL. */ Channel *topChanPtr; /* Refers to topmost channel in a stack. Never * NULL. */ Channel *bottomChanPtr; /* Refers to bottommost channel in a stack. * This channel can be relied on to live as * long as the channel state. Never NULL. */ struct ChannelState *nextCSPtr; /* Next in list of channels currently open. */ Tcl_ThreadId managingThread;/* TIP #10: Id of the thread managing this * stack of channels. */ /* * TIP #219 ... Info for the I/O system ... * Error message set by channel drivers, for the propagation of arbitrary * Tcl errors. This information, if present (chanMsg not NULL), takes * precedence over a posix error code returned by a channel operation. */ Tcl_Obj* chanMsg; Tcl_Obj* unreportedMsg; /* Non-NULL if an error report was deferred * because it happened in the background. The * value is the chanMg, if any. #219's * companion to 'unreportedError'. */ } ChannelState; /* * Values for the flags field in Channel. Any ORed combination of the * following flags can be stored in the field. These flags record various * options and state bits about the channel. In addition to the flags below, * the channel can also have TCL_READABLE (1<<1) and TCL_WRITABLE (1<<2) set. */ #define CHANNEL_NONBLOCKING (1<<3) /* Channel is currently in nonblocking * mode. */ #define CHANNEL_LINEBUFFERED (1<<4) /* Output to the channel must be * flushed after every newline. */ #define CHANNEL_UNBUFFERED (1<<5) /* Output to the channel must always * be flushed immediately. */ #define BUFFER_READY (1<<6) /* Current output buffer (the * curOutPtr field in the channel * structure) should be output as soon * as possible even though it may not * be full. */ #define BG_FLUSH_SCHEDULED (1<<7) /* A background flush of the queued * output buffers has been * scheduled. */ #define CHANNEL_CLOSED (1<<8) /* Channel has been closed. No further * Tcl-level IO on the channel is * allowed. */ #define CHANNEL_EOF (1<<9) /* EOF occurred on this channel. This * bit is cleared before every input * operation. */ #define CHANNEL_STICKY_EOF (1<<10) /* EOF occurred on this channel * because we saw the input * eofChar. This bit prevents clearing * of the EOF bit before every input * operation. */ #define CHANNEL_BLOCKED (1<<11) /* EWOULDBLOCK or EAGAIN occurred on * this channel. This bit is cleared * before every input or output * operation. */ #define INPUT_SAW_CR (1<<12) /* Channel is in CRLF eol input * translation mode and the last byte * seen was a "\r". */ #define INPUT_NEED_NL (1<<15) /* Saw a '\r' at end of last buffer, * and there should be a '\n' at * beginning of next buffer. */ #define CHANNEL_DEAD (1<<13) /* The channel has been closed by the * exit handler (on exit) but not * deallocated. When any IO operation * sees this flag on a channel, it * does not call driver level * functions to avoid referring to * deallocated data. */ #define CHANNEL_NEED_MORE_DATA (1<<14) /* The last input operation failed * because there was not enough data * to complete the operation. This * flag is set when gets fails to get * a complete line or when read fails * to get a complete character. When * set, file events will not be * delivered for buffered data until * the state of the channel * changes. */ #define CHANNEL_RAW_MODE (1<<16) /* When set, notes that the Raw API is * being used. */ #ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING #define CHANNEL_TIMER_FEV (1<<17) /* When set the event we are notified * by is a fileevent generated by a * timer. We don't know if the driver * has more data and should not try to * read from it. If the system needs * more than is in the buffers out * read routines will simulate a short * read (0 characters read) */ #define CHANNEL_HAS_MORE_DATA (1<<18) /* Set by NotifyChannel for a channel * if and only if the channel is * configured non-blocking, the driver * for said channel has no * blockmodeproc, and data has arrived * for reading at the OS level). A * GetInput will pass reading from the * driver if the channel is * non-blocking, without blockmode * proc and the flag has not been set. * A read will be performed if the * flag is set. This will reset the * flag as well. */ #endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */ #define CHANNEL_INCLOSE (1<<19) /* Channel is currently being closed. * Its structures are still live and * usable, but it may not be closed * again from within the close * handler. */ #define CHANNEL_TAINTED (1<<20) /* Channel stack structure has changed. * Used by Channel Tcl_Obj type to * determine if we have to revalidate * the channel. */ /* * For each channel handler registered in a call to Tcl_CreateChannelHandler, * there is one record of the following type. All of records for a specific * channel are chained together in a singly linked list which is stored in the * channel structure. */ typedef struct ChannelHandler { Channel *chanPtr; /* The channel structure for this channel. */ int mask; /* Mask of desired events. */ Tcl_ChannelProc *proc; /* Procedure to call in the type of * Tcl_CreateChannelHandler. */ ClientData clientData; /* Argument to pass to procedure. */ struct ChannelHandler *nextPtr; /* Next one in list of registered handlers. */ } ChannelHandler; /* * This structure keeps track of the current ChannelHandler being invoked in * the current invocation of ChannelHandlerEventProc. There is a potential * problem if a ChannelHandler is deleted while it is the current one, since * ChannelHandlerEventProc needs to look at the nextPtr field. To handle this * problem, structures of the type below indicate the next handler to be * processed for any (recursively nested) dispatches in progress. The * nextHandlerPtr field is updated if the handler being pointed to is deleted. * The nextPtr field is used to chain together all recursive invocations, so * that Tcl_DeleteChannelHandler can find all the recursively nested * invocations of ChannelHandlerEventProc and compare the handler being * deleted against the NEXT handler to be invoked in that invocation; when it * finds such a situation, Tcl_DeleteChannelHandler updates the nextHandlerPtr * field of the structure to the next handler. */ typedef struct NextChannelHandler { ChannelHandler *nextHandlerPtr; /* The next handler to be invoked in this * invocation. */ struct NextChannelHandler *nestedHandlerPtr; /* Next nested invocation of * ChannelHandlerEventProc. */ } NextChannelHandler; /* * The following structure describes the event that is added to the Tcl event * queue by the channel handler check procedure. */ typedef struct ChannelHandlerEvent { Tcl_Event header; /* Standard header for all events. */ Channel *chanPtr; /* The channel that is ready. */ int readyMask; /* Events that have occurred. */ } ChannelHandlerEvent; /* * The following structure is used by Tcl_GetsObj() to encapsulates the state * for a "gets" operation. */ typedef struct GetsState { Tcl_Obj *objPtr; /* The object to which UTF-8 characters will * be appended. */ char **dstPtr; /* Pointer into objPtr's string rep where next * character should be stored. */ Tcl_Encoding encoding; /* The encoding to use to convert raw bytes to * UTF-8. */ ChannelBuffer *bufPtr; /* The current buffer of raw bytes being * emptied. */ Tcl_EncodingState state; /* The encoding state just before the last * external to UTF-8 conversion in * FilterInputBytes(). */ int rawRead; /* The number of bytes removed from bufPtr in * the last call to FilterInputBytes(). */ int bytesWrote; /* The number of bytes of UTF-8 data appended * to objPtr during the last call to * FilterInputBytes(). */ int charsWrote; /* The corresponding number of UTF-8 * characters appended to objPtr during the * last call to FilterInputBytes(). */ int totalChars; /* The total number of UTF-8 characters * appended to objPtr so far, just before the * last call to FilterInputBytes(). */ } GetsState;  /* * Local Variables: * mode: c * c-basic-offset: 4 * fill-column: 78 * End: */

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