298 lines
11 KiB
C
298 lines
11 KiB
C
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/*
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* tclIO.h --
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*
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* This file provides the generic portions (those that are the same on
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* all platforms and for all channel types) of Tcl's IO facilities.
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*
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* Copyright (c) 1998-2000 Ajuba Solutions
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* Copyright (c) 1995-1997 Sun Microsystems, Inc.
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*
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* See the file "license.terms" for information on usage and redistribution of
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* this file, and for a DISCLAIMER OF ALL WARRANTIES.
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*/
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/*
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* Make sure that both EAGAIN and EWOULDBLOCK are defined. This does not
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* compile on systems where neither is defined. We want both defined so that
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* we can test safely for both. In the code we still have to test for both
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* because there may be systems on which both are defined and have different
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* values.
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*/
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#if ((!defined(EWOULDBLOCK)) && (defined(EAGAIN)))
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# define EWOULDBLOCK EAGAIN
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#endif
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#if ((!defined(EAGAIN)) && (defined(EWOULDBLOCK)))
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# define EAGAIN EWOULDBLOCK
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#endif
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#if ((!defined(EAGAIN)) && (!defined(EWOULDBLOCK)))
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#error one of EWOULDBLOCK or EAGAIN must be defined
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#endif
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/*
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* struct ChannelBuffer:
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*
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* Buffers data being sent to or from a channel.
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*/
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typedef struct ChannelBuffer {
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int refCount; /* Current uses count */
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int nextAdded; /* The next position into which a character
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* will be put in the buffer. */
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int nextRemoved; /* Position of next byte to be removed from
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* the buffer. */
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int bufLength; /* How big is the buffer? */
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struct ChannelBuffer *nextPtr;
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/* Next buffer in chain. */
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char buf[TCLFLEXARRAY]; /* Placeholder for real buffer. The real
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* buffer occuppies this space + bufSize-1
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* bytes. This must be the last field in the
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* structure. */
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} ChannelBuffer;
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#define CHANNELBUFFER_HEADER_SIZE TclOffset(ChannelBuffer, buf)
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/*
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* How much extra space to allocate in buffer to hold bytes from previous
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* buffer (when converting to UTF-8) or to hold bytes that will go to next
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* buffer (when converting from UTF-8).
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*/
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#define BUFFER_PADDING 16
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/*
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* The following defines the *default* buffer size for channels.
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*/
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#define CHANNELBUFFER_DEFAULT_SIZE (1024 * 4)
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/*
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* The following structure describes the information saved from a call to
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* "fileevent". This is used later when the event being waited for to invoke
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* the saved script in the interpreter designed in this record.
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*/
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typedef struct EventScriptRecord {
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struct Channel *chanPtr; /* The channel for which this script is
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* registered. This is used only when an error
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* occurs during evaluation of the script, to
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* delete the handler. */
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Tcl_Obj *scriptPtr; /* Script to invoke. */
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Tcl_Interp *interp; /* In what interpreter to invoke script? */
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int mask; /* Events must overlap current mask for the
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* stored script to be invoked. */
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struct EventScriptRecord *nextPtr;
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/* Next in chain of records. */
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} EventScriptRecord;
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/*
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* struct Channel:
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*
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* One of these structures is allocated for each open channel. It contains
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* data specific to the channel but which belongs to the generic part of the
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* Tcl channel mechanism, and it points at an instance specific (and type
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* specific) instance data, and at a channel type structure.
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*/
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typedef struct Channel {
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struct ChannelState *state; /* Split out state information */
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ClientData instanceData; /* Instance-specific data provided by creator
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* of channel. */
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const Tcl_ChannelType *typePtr; /* Pointer to channel type structure. */
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struct Channel *downChanPtr;/* Refers to channel this one was stacked
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* upon. This reference is NULL for normal
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* channels. See Tcl_StackChannel. */
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struct Channel *upChanPtr; /* Refers to the channel above stacked this
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* one. NULL for the top most channel. */
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/*
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* Intermediate buffers to hold pre-read data for consumption by a newly
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* stacked transformation. See 'Tcl_StackChannel'.
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*/
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ChannelBuffer *inQueueHead; /* Points at first buffer in input queue. */
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ChannelBuffer *inQueueTail; /* Points at last buffer in input queue. */
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int refCount;
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} Channel;
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/*
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* struct ChannelState:
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*
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* One of these structures is allocated for each open channel. It contains
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* data specific to the channel but which belongs to the generic part of the
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* Tcl channel mechanism, and it points at an instance specific (and type
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* specific) instance data, and at a channel type structure.
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*/
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typedef struct ChannelState {
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char *channelName; /* The name of the channel instance in Tcl
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* commands. Storage is owned by the generic
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* IO code, is dynamically allocated. */
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int flags; /* ORed combination of the flags defined
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* below. */
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Tcl_Encoding encoding; /* Encoding to apply when reading or writing
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* data on this channel. NULL means no
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* encoding is applied to data. */
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Tcl_EncodingState inputEncodingState;
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/* Current encoding state, used when
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* converting input data bytes to UTF-8. */
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int inputEncodingFlags; /* Encoding flags to pass to conversion
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* routine when converting input data bytes to
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* UTF-8. May be TCL_ENCODING_START before
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* converting first byte and TCL_ENCODING_END
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* when EOF is seen. */
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Tcl_EncodingState outputEncodingState;
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/* Current encoding state, used when
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* converting UTF-8 to output data bytes. */
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int outputEncodingFlags; /* Encoding flags to pass to conversion
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* routine when converting UTF-8 to output
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* data bytes. May be TCL_ENCODING_START
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* before converting first byte and
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* TCL_ENCODING_END when EOF is seen. */
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TclEolTranslation inputTranslation;
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/* What translation to apply for end of line
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* sequences on input? */
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TclEolTranslation outputTranslation;
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/* What translation to use for generating end
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* of line sequences in output? */
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int inEofChar; /* If nonzero, use this as a signal of EOF on
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* input. */
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int outEofChar; /* If nonzero, append this to the channel when
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* it is closed if it is open for writing. */
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int unreportedError; /* Non-zero if an error report was deferred
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* because it happened in the background. The
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* value is the POSIX error code. */
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int refCount; /* How many interpreters hold references to
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* this IO channel? */
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struct CloseCallback *closeCbPtr;
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/* Callbacks registered to be called when the
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* channel is closed. */
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char *outputStage; /* Temporary staging buffer used when
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* translating EOL before converting from
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* UTF-8 to external form. */
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ChannelBuffer *curOutPtr; /* Current output buffer being filled. */
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ChannelBuffer *outQueueHead;/* Points at first buffer in output queue. */
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ChannelBuffer *outQueueTail;/* Points at last buffer in output queue. */
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ChannelBuffer *saveInBufPtr;/* Buffer saved for input queue - eliminates
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* need to allocate a new buffer for "gets"
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* that crosses buffer boundaries. */
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ChannelBuffer *inQueueHead; /* Points at first buffer in input queue. */
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ChannelBuffer *inQueueTail; /* Points at last buffer in input queue. */
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struct ChannelHandler *chPtr;/* List of channel handlers registered for
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* this channel. */
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int interestMask; /* Mask of all events this channel has
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* handlers for. */
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EventScriptRecord *scriptRecordPtr;
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/* Chain of all scripts registered for event
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* handlers ("fileevent") on this channel. */
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int bufSize; /* What size buffers to allocate? */
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Tcl_TimerToken timer; /* Handle to wakeup timer for this channel. */
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struct CopyState *csPtrR; /* State of background copy for which channel
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* is input, or NULL. */
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struct CopyState *csPtrW; /* State of background copy for which channel
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* is output, or NULL. */
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Channel *topChanPtr; /* Refers to topmost channel in a stack. Never
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* NULL. */
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Channel *bottomChanPtr; /* Refers to bottommost channel in a stack.
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* This channel can be relied on to live as
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* long as the channel state. Never NULL. */
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struct ChannelState *nextCSPtr;
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/* Next in list of channels currently open. */
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Tcl_ThreadId managingThread;/* TIP #10: Id of the thread managing this
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* stack of channels. */
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/*
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* TIP #219 ... Info for the I/O system ...
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* Error message set by channel drivers, for the propagation of arbitrary
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* Tcl errors. This information, if present (chanMsg not NULL), takes
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* precedence over a posix error code returned by a channel operation.
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*/
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Tcl_Obj* chanMsg;
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Tcl_Obj* unreportedMsg; /* Non-NULL if an error report was deferred
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* because it happened in the background. The
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* value is the chanMg, if any. #219's
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* companion to 'unreportedError'. */
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int epoch; /* Used to test validity of stored channelname
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* lookup results. */
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} ChannelState;
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/*
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* Values for the flags field in Channel. Any ORed combination of the
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* following flags can be stored in the field. These flags record various
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* options and state bits about the channel. In addition to the flags below,
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* the channel can also have TCL_READABLE (1<<1) and TCL_WRITABLE (1<<2) set.
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*/
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#define CHANNEL_NONBLOCKING (1<<3) /* Channel is currently in nonblocking
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* mode. */
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#define CHANNEL_LINEBUFFERED (1<<4) /* Output to the channel must be
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* flushed after every newline. */
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#define CHANNEL_UNBUFFERED (1<<5) /* Output to the channel must always
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* be flushed immediately. */
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#define BG_FLUSH_SCHEDULED (1<<7) /* A background flush of the queued
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* output buffers has been
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* scheduled. */
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#define CHANNEL_CLOSED (1<<8) /* Channel has been closed. No further
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* Tcl-level IO on the channel is
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* allowed. */
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#define CHANNEL_EOF (1<<9) /* EOF occurred on this channel. This
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* bit is cleared before every input
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* operation. */
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#define CHANNEL_STICKY_EOF (1<<10) /* EOF occurred on this channel
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* because we saw the input
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* eofChar. This bit prevents clearing
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* of the EOF bit before every input
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* operation. */
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#define CHANNEL_BLOCKED (1<<11) /* EWOULDBLOCK or EAGAIN occurred on
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* this channel. This bit is cleared
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* before every input or output
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* operation. */
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#define INPUT_SAW_CR (1<<12) /* Channel is in CRLF eol input
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* translation mode and the last byte
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* seen was a "\r". */
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#define CHANNEL_DEAD (1<<13) /* The channel has been closed by the
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* exit handler (on exit) but not
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* deallocated. When any IO operation
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* sees this flag on a channel, it
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* does not call driver level
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* functions to avoid referring to
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* deallocated data. */
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#define CHANNEL_NEED_MORE_DATA (1<<14) /* The last input operation failed
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* because there was not enough data
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* to complete the operation. This
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* flag is set when gets fails to get
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* a complete line or when read fails
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* to get a complete character. When
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* set, file events will not be
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* delivered for buffered data until
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* the state of the channel
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* changes. */
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#define CHANNEL_RAW_MODE (1<<16) /* When set, notes that the Raw API is
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* being used. */
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#define CHANNEL_INCLOSE (1<<19) /* Channel is currently being closed.
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* Its structures are still live and
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* usable, but it may not be closed
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* again from within the close
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* handler. */
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#define CHANNEL_CLOSEDWRITE (1<<21) /* Channel write side has been closed.
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* No further Tcl-level write IO on
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* the channel is allowed. */
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/*
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* The length of time to wait between synthetic timer events. Must be zero or
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* bad things tend to happen.
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*/
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#define SYNTHETIC_EVENT_TIME 0
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/*
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* Local Variables:
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* mode: c
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* c-basic-offset: 4
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* fill-column: 78
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* End:
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*/
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