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428
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1 /* Generic stream implementation -- header file.
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2 Copyright (C) 1995 Free Software Foundation, Inc.
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3 Copyright (C) 1996 Ben Wing.
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4
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5 This file is part of XEmacs.
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6
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7 XEmacs is free software; you can redistribute it and/or modify it
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8 under the terms of the GNU General Public License as published by the
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9 Free Software Foundation; either version 2, or (at your option) any
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10 later version.
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11
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12 XEmacs is distributed in the hope that it will be useful, but WITHOUT
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13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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15 for more details.
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16
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17 You should have received a copy of the GNU General Public License
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18 along with XEmacs; see the file COPYING. If not, write to
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19 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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20 Boston, MA 02111-1307, USA. */
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21
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22 /* Synched up with: Not in FSF. */
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23
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24 /* Written by Ben Wing. */
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25
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440
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26 #ifndef INCLUDED_lstream_h_
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27 #define INCLUDED_lstream_h_
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428
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28
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29 /************************************************************************/
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30 /* definition of Lstream object */
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31 /************************************************************************/
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32
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33 DECLARE_LRECORD (lstream, struct lstream);
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34 #define XLSTREAM(x) XRECORD (x, lstream, struct lstream)
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35 #define XSETLSTREAM(x, p) XSETRECORD (x, p, lstream)
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617
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36 #define wrap_lstream(p) wrap_record (p, lstream)
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428
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37 #define LSTREAMP(x) RECORDP (x, lstream)
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38 /* #define CHECK_LSTREAM(x) CHECK_RECORD (x, lstream)
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39 Lstream pointers should never escape to the Lisp level, so
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40 functions should not be doing this. */
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41
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42 #ifndef EOF
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43 #define EOF (-1)
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44 #endif
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45
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665
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46 /* The have been some arguments over the what the type should be that
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47 specifies a count of bytes in a data block to be written out or read in,
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48 using Lstream_read(), Lstream_write(), and related functions.
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49 Originally it was long, which worked fine; Martin "corrected" these to
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50 size_t and ssize_t on the grounds that this is theoretically cleaner and
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51 is in keeping with the C standards. Unfortunately, this practice is
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52 horribly error-prone due to design flaws in the way that mixed
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53 signed/unsigned arithmetic happens. In fact, by doing this change,
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54 Martin introduced a subtle but fatal error that caused the operation of
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55 sending large mail messages to the SMTP server under Windows to fail.
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56 By putting all values back to be signed, avoiding any signed/unsigned
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57 mixing, the bug immediately went away. The type then in use was
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58 Lstream_Data_Count, so that it be reverted cleanly if a vote came to
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59 that. Now it is Bytecount.
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60
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61 Some earlier comments about why the type must be signed: This MUST BE
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62 SIGNED, since it also is used in functions that return the number of
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63 bytes actually read to or written from in an operation, and these
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64 functions can return -1 to signal error.
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462
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65
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66 Note that the standard Unix read() and write() functions define the
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67 count going in as a size_t, which is UNSIGNED, and the count going
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68 out as an ssize_t, which is SIGNED. This is a horrible design
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69 flaw. Not only is it highly likely to lead to logic errors when a
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70 -1 gets interpreted as a large positive number, but operations are
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71 bound to fail in all sorts of horrible ways when a number in the
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72 upper-half of the size_t range is passed in -- this number is
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73 unrepresentable as an ssize_t, so code that checks to see how many
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74 bytes are actually written (which is mandatory if you are dealing
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75 with certain types of devices) will get completely screwed up.
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665
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76
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77 --ben
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462
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78 */
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79
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428
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80 typedef enum lstream_buffering
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81 {
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82 /* No buffering. */
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83 LSTREAM_UNBUFFERED,
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84 /* Buffer until a '\n' character is reached. */
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85 LSTREAM_LINE_BUFFERED,
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86 /* Buffer in standard-size (i.e. 512-byte) blocks. */
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87 LSTREAM_BLOCK_BUFFERED,
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88 /* Buffer in blocks of a specified size. */
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89 LSTREAM_BLOCKN_BUFFERED,
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90 /* Buffer until the stream is closed (only applies to write-only
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91 streams). Only one call to the stream writer will be made,
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92 and that is when the stream is closed. */
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93 LSTREAM_UNLIMITED
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94 } Lstream_buffering;
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95
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96 /* Methods defining how this stream works. Some may be undefined. */
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97
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98 /* We do not implement the seek/tell paradigm. I tried to do that,
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99 but getting the semantics right in the presence of buffering is
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100 extremely tricky and very error-prone and basically not worth it.
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101 This is especially the case with complicated streams like
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102 decoding streams -- the seek pointer in this case can't be a single
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103 integer but has to be a whole complicated structure that records
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104 all of the stream's state at the time.
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105
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106 Rewind semantics are generally easy to implement, so we do provide
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107 a rewind method. Even rewind() may not be available on a stream,
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108 however -- e.g. on process output. */
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109
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110 typedef struct lstream_implementation
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111 {
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442
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112 const char *name;
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665
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113 Bytecount size; /* Number of additional bytes to be
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462
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114 allocated with this stream. Access this
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115 data using Lstream_data(). */
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428
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116 /* Read some data from the stream's end and store it into DATA, which
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117 can hold SIZE bytes. Return the number of bytes read. A return
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118 value of 0 means no bytes can be read at this time. This may
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119 be because of an EOF, or because there is a granularity greater
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120 than one byte that the stream imposes on the returned data, and
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121 SIZE is less than this granularity. (This will happen frequently
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122 for streams that need to return whole characters, because
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123 Lstream_read() calls the reader function repeatedly until it
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124 has the number of bytes it wants or until 0 is returned.)
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125 The lstream functions do not treat a 0 return as EOF or do
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126 anything special; however, the calling function will interpret
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127 any 0 it gets back as EOF. This will normally not happen unless
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128 the caller calls Lstream_read() with a very small size.
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129
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130 This function can be NULL if the stream is output-only. */
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442
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131 /* The omniscient mly, blinded by the irresistible thrall of Common
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428
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132 Lisp, thinks that it is bogus that the types and implementations
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133 of input and output streams are the same. */
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665
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134 Bytecount (*reader) (Lstream *stream, unsigned char *data,
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135 Bytecount size);
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428
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136 /* Send some data to the stream's end. Data to be sent is in DATA
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137 and is SIZE bytes. Return the number of bytes sent. This
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138 function can send and return fewer bytes than is passed in; in
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139 that case, the function will just be called again until there is
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140 no data left or 0 is returned. A return value of 0 means that no
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141 more data can be currently stored, but there is no error; the
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142 data will be squirrelled away until the writer can accept
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143 data. (This is useful, e.g., of you're dealing with a
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144 non-blocking file descriptor and are getting EWOULDBLOCK errors.)
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145 This function can be NULL if the stream is input-only. */
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665
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146 Bytecount (*writer) (Lstream *stream, const unsigned char *data,
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147 Bytecount size);
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428
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148 /* Return non-zero if the last write operation on the stream resulted
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149 in an attempt to block (EWOULDBLOCK). If this method does not
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150 exists, the implementation returns 0 */
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151 int (*was_blocked_p) (Lstream *stream);
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152 /* Rewind the stream. If this is NULL, the stream is not seekable. */
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153 int (*rewinder) (Lstream *stream);
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154 /* Indicate whether this stream is seekable -- i.e. it can be rewound.
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155 This method is ignored if the stream does not have a rewind
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156 method. If this method is not present, the result is determined
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157 by whether a rewind method is present. */
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158 int (*seekable_p) (Lstream *stream);
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159 /* Perform any additional operations necessary to flush the
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160 data in this stream. */
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161 int (*flusher) (Lstream *stream);
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162 /* Perform any additional operations necessary to close this
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163 stream down. May be NULL. This function is called when
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164 Lstream_close() is called or when the stream is garbage-
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165 collected. When this function is called, all pending data
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166 in the stream will already have been written out. */
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167 int (*closer) (Lstream *stream);
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168 /* Mark this object for garbage collection. Same semantics as
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169 a standard Lisp_Object marker. This function can be NULL. */
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170 Lisp_Object (*marker) (Lisp_Object lstream);
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171 } Lstream_implementation;
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172
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173 #define DEFINE_LSTREAM_IMPLEMENTATION(name,c_name,size) \
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174 Lstream_implementation c_name[1] = \
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175 { { (name), (size) } }
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176
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177 #define LSTREAM_FL_IS_OPEN 1
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178 #define LSTREAM_FL_READ 2
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179 #define LSTREAM_FL_WRITE 4
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180 #define LSTREAM_FL_NO_PARTIAL_CHARS 8
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181 #define LSTREAM_FL_CLOSE_AT_DISKSAVE 16
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182
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183 struct lstream
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184 {
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185 struct lcrecord_header header;
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442
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186 const Lstream_implementation *imp; /* methods for this stream */
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428
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187 Lstream_buffering buffering; /* type of buffering in use */
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665
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188 Bytecount buffering_size; /* number of bytes buffered */
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428
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189
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190 unsigned char *in_buffer; /* holds characters read from stream end */
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665
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191 Bytecount in_buffer_size; /* allocated size of buffer */
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192 Bytecount in_buffer_current; /* number of characters in buffer */
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193 Bytecount in_buffer_ind; /* pointer to next character to
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462
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194 take from buffer */
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428
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195
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196 unsigned char *out_buffer; /* holds characters to write to stream end */
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665
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197 Bytecount out_buffer_size; /* allocated size of buffer */
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198 Bytecount out_buffer_ind; /* pointer to next buffer spot to
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462
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199 write a character */
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428
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200
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201 /* The unget buffer is more or less a stack -- things get pushed
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202 onto the end and read back from the end. Lstream_read()
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203 basically reads backwards from the end to get stuff; Lstream_unread()
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204 similarly has to push the data on backwards. */
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205 unsigned char *unget_buffer; /* holds characters pushed back onto input */
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665
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206 Bytecount unget_buffer_size; /* allocated size of buffer */
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207 Bytecount unget_buffer_ind; /* pointer to next buffer spot
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462
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208 to write a character */
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428
|
209
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665
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210 Bytecount byte_count;
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456
|
211 int flags;
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212 max_align_t data[1];
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428
|
213 };
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214
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215 #define LSTREAM_TYPE_P(lstr, type) \
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216 ((lstr)->imp == lstream_##type)
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217
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|
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218 #ifdef ERROR_CHECK_TYPECHECK
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442
|
219 INLINE_HEADER struct lstream *
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428
|
220 error_check_lstream_type (struct lstream *stream,
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442
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221 const Lstream_implementation *imp);
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222 INLINE_HEADER struct lstream *
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428
|
223 error_check_lstream_type (struct lstream *stream,
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442
|
224 const Lstream_implementation *imp)
|
|
428
|
225 {
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|
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226 assert (stream->imp == imp);
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227 return stream;
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|
|
228 }
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|
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229 # define LSTREAM_TYPE_DATA(lstr, type) \
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230 ((struct type##_stream *) \
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231 Lstream_data (error_check_lstream_type(lstr, lstream_##type)))
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232 #else
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233 # define LSTREAM_TYPE_DATA(lstr, type) \
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234 ((struct type##_stream *) Lstream_data (lstr))
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|
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235 #endif
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236
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|
|
237 /* Declare that lstream-type TYPE has method M; used in
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238 initialization routines */
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239 #define LSTREAM_HAS_METHOD(type, m) \
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240 (lstream_##type->m = type##_##m)
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241
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|
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242
|
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442
|
243 Lstream *Lstream_new (const Lstream_implementation *imp,
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244 const char *mode);
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428
|
245 void Lstream_reopen (Lstream *lstr);
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246 void Lstream_set_buffering (Lstream *lstr, Lstream_buffering buffering,
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247 int buffering_size);
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248 int Lstream_flush (Lstream *lstr);
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249 int Lstream_flush_out (Lstream *lstr);
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250 int Lstream_fputc (Lstream *lstr, int c);
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251 int Lstream_fgetc (Lstream *lstr);
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252 void Lstream_fungetc (Lstream *lstr, int c);
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665
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253 Bytecount Lstream_read (Lstream *lstr, void *data,
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254 Bytecount size);
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255 Bytecount Lstream_write (Lstream *lstr, const void *data,
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256 Bytecount size);
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428
|
257 int Lstream_was_blocked_p (Lstream *lstr);
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665
|
258 void Lstream_unread (Lstream *lstr, const void *data, Bytecount size);
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428
|
259 int Lstream_rewind (Lstream *lstr);
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260 int Lstream_seekable_p (Lstream *lstr);
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261 int Lstream_close (Lstream *lstr);
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262 void Lstream_delete (Lstream *lstr);
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263 void Lstream_set_character_mode (Lstream *str);
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264
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265 /* Call the function equivalent if the out buffer is full. Otherwise,
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266 add to the end of the out buffer and, if line buffering is called for
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267 and the character marks the end of a line, write out the buffer. */
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268
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269 #define Lstream_putc(stream, c) \
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270 ((stream)->out_buffer_ind >= (stream)->out_buffer_size ? \
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271 Lstream_fputc (stream, c) : \
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272 ((stream)->out_buffer[(stream)->out_buffer_ind++] = \
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273 (unsigned char) (c), \
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274 (stream)->byte_count++, \
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275 (stream)->buffering == LSTREAM_LINE_BUFFERED && \
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276 (stream)->out_buffer[(stream)->out_buffer_ind - 1] == '\n' ? \
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277 Lstream_flush_out (stream) : 0))
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278
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|
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279 /* Retrieve from unget buffer if there are any characters there;
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280 else retrieve from in buffer if there's anything there;
|
|
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281 else call the function equivalent */
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|
|
282 #define Lstream_getc(stream) \
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|
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283 ((stream)->unget_buffer_ind > 0 ? \
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|
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284 ((stream)->byte_count++, \
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|
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285 (stream)->unget_buffer[--(stream)->unget_buffer_ind]) : \
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286 (stream)->in_buffer_ind < (stream)->in_buffer_current ? \
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|
|
287 ((stream)->byte_count++, \
|
|
|
288 (stream)->in_buffer[(stream)->in_buffer_ind++]) : \
|
|
|
289 Lstream_fgetc (stream))
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|
|
290
|
|
|
291 /* Add to the end if it won't overflow buffer; otherwise call the
|
|
|
292 function equivalent */
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|
|
293 #define Lstream_ungetc(stream, c) \
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|
|
294 ((stream)->unget_buffer_ind >= (stream)->unget_buffer_size ? \
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|
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295 Lstream_fungetc (stream, c) : \
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|
|
296 (void) ((stream)->byte_count--, \
|
|
|
297 ((stream)->unget_buffer[(stream)->unget_buffer_ind++] = \
|
|
|
298 (unsigned char) (c))))
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|
|
299
|
|
|
300 #define Lstream_data(stream) ((void *) ((stream)->data))
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|
|
301 #define Lstream_byte_count(stream) ((stream)->byte_count)
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|
|
302
|
|
|
303
|
|
|
304 /************************************************************************/
|
|
|
305 /* working with an Lstream as a stream of Emchars */
|
|
|
306 /************************************************************************/
|
|
|
307
|
|
|
308 #ifdef MULE
|
|
|
309
|
|
|
310 #ifndef BYTE_ASCII_P
|
|
|
311 #include "mule-charset.h"
|
|
|
312 #endif
|
|
|
313
|
|
442
|
314 INLINE_HEADER Emchar Lstream_get_emchar (Lstream *stream);
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|
|
315 INLINE_HEADER Emchar
|
|
428
|
316 Lstream_get_emchar (Lstream *stream)
|
|
|
317 {
|
|
|
318 int c = Lstream_getc (stream);
|
|
444
|
319 return (c < 0x80 /* c == EOF || BYTE_ASCII_P (c) */
|
|
|
320 ? (Emchar) c
|
|
|
321 : Lstream_get_emchar_1 (stream, c));
|
|
428
|
322 }
|
|
|
323
|
|
442
|
324 INLINE_HEADER int Lstream_put_emchar (Lstream *stream, Emchar ch);
|
|
|
325 INLINE_HEADER int
|
|
428
|
326 Lstream_put_emchar (Lstream *stream, Emchar ch)
|
|
|
327 {
|
|
|
328 return CHAR_ASCII_P (ch) ?
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|
|
329 Lstream_putc (stream, ch) :
|
|
|
330 Lstream_fput_emchar (stream, ch);
|
|
|
331 }
|
|
|
332
|
|
442
|
333 INLINE_HEADER void Lstream_unget_emchar (Lstream *stream, Emchar ch);
|
|
|
334 INLINE_HEADER void
|
|
428
|
335 Lstream_unget_emchar (Lstream *stream, Emchar ch)
|
|
|
336 {
|
|
|
337 if (CHAR_ASCII_P (ch))
|
|
|
338 Lstream_ungetc (stream, ch);
|
|
|
339 else
|
|
|
340 Lstream_funget_emchar (stream, ch);
|
|
|
341 }
|
|
|
342 #else /* not MULE */
|
|
|
343
|
|
|
344 # define Lstream_get_emchar(stream) Lstream_getc (stream)
|
|
|
345 # define Lstream_put_emchar(stream, ch) Lstream_putc (stream, ch)
|
|
|
346 # define Lstream_unget_emchar(stream, ch) Lstream_ungetc (stream, ch)
|
|
|
347
|
|
|
348 #endif /* not MULE */
|
|
|
349
|
|
|
350
|
|
|
351 /************************************************************************/
|
|
|
352 /* Lstream implementations */
|
|
|
353 /************************************************************************/
|
|
|
354
|
|
|
355 /* Flags we can pass to the filedesc and stdio streams. */
|
|
|
356
|
|
|
357 /* If set, close the descriptor or FILE * when the stream is closed. */
|
|
|
358 #define LSTR_CLOSING 1
|
|
|
359
|
|
|
360 /* If set, allow quitting out of the actual I/O. */
|
|
|
361 #define LSTR_ALLOW_QUIT 2
|
|
|
362
|
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363 /* If set and filedesc_stream_set_pty_flushing() has been called
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364 on the stream, do not send more than pty_max_bytes on a single
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365 line without flushing the data out using the eof_char. */
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366 #define LSTR_PTY_FLUSHING 4
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367
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368 /* If set, an EWOULDBLOCK error is not treated as an error but
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369 simply causes the write function to return 0 as the number
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370 of bytes written out. */
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371 #define LSTR_BLOCKED_OK 8
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372
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373 Lisp_Object make_stdio_input_stream (FILE *stream, int flags);
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374 Lisp_Object make_stdio_output_stream (FILE *stream, int flags);
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375 Lisp_Object make_filedesc_input_stream (int filedesc, int offset, int count,
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376 int flags);
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377 Lisp_Object make_filedesc_output_stream (int filedesc, int offset, int count,
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378 int flags);
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379 void filedesc_stream_set_pty_flushing (Lstream *stream,
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380 int pty_max_bytes,
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665
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381 Intbyte eof_char);
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428
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382 int filedesc_stream_fd (Lstream *stream);
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383 Lisp_Object make_lisp_string_input_stream (Lisp_Object string,
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384 Bytecount offset,
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385 Bytecount len);
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462
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386 Lisp_Object make_fixed_buffer_input_stream (const void *buf,
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665
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387 Bytecount size);
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462
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388 Lisp_Object make_fixed_buffer_output_stream (void *buf,
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665
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389 Bytecount size);
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442
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390 const unsigned char *fixed_buffer_input_stream_ptr (Lstream *stream);
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428
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391 unsigned char *fixed_buffer_output_stream_ptr (Lstream *stream);
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392 Lisp_Object make_resizing_buffer_output_stream (void);
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393 unsigned char *resizing_buffer_stream_ptr (Lstream *stream);
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394 Lisp_Object make_dynarr_output_stream (unsigned_char_dynarr *dyn);
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395 #define LSTR_SELECTIVE 1
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396 #define LSTR_IGNORE_ACCESSIBLE 2
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665
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397 Lisp_Object make_lisp_buffer_input_stream (struct buffer *buf, Charbpos start,
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398 Charbpos end, int flags);
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399 Lisp_Object make_lisp_buffer_output_stream (struct buffer *buf, Charbpos pos,
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428
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400 int flags);
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665
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401 Charbpos lisp_buffer_stream_startpos (Lstream *stream);
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428
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402
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440
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403 #endif /* INCLUDED_lstream_h_ */
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