summaryrefslogtreecommitdiff
path: root/mysys/mf_iocache2.c
blob: f1ea21c2a473e149967cc00402b711d741b123c7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
/* Copyright (C) 2000 MySQL AB

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

/*
  More functions to be used with IO_CACHE files
*/

#define MAP_TO_USE_RAID
#include "mysys_priv.h"
#include <m_string.h>
#include <stdarg.h>
#include <m_ctype.h>

my_off_t my_b_append_tell(IO_CACHE* info)
{
  /*
    Prevent optimizer from putting res in a register when debugging
    we need this to be able to see the value of res when the assert fails
  */
  dbug_volatile my_off_t res; 

  /*
    We need to lock the append buffer mutex to keep flush_io_cache()
    from messing with the variables that we need in order to provide the
    answer to the question.
  */
#ifdef THREAD
  pthread_mutex_lock(&info->append_buffer_lock);
#endif
#ifndef DBUG_OFF
  /*
    Make sure EOF is where we think it is. Note that we cannot just use
    my_tell() because we have a reader thread that could have left the
    file offset in a non-EOF location
  */
  {
    volatile my_off_t save_pos;
    save_pos = my_tell(info->file,MYF(0));
    my_seek(info->file,(my_off_t)0,MY_SEEK_END,MYF(0));
    /*
      Save the value of my_tell in res so we can see it when studying coredump
    */
    DBUG_ASSERT(info->end_of_file - (info->append_read_pos-info->write_buffer)
		== (res=my_tell(info->file,MYF(0))));
    my_seek(info->file,save_pos,MY_SEEK_SET,MYF(0));
  }
#endif  
  res = info->end_of_file + (info->write_pos-info->append_read_pos);
#ifdef THREAD
  pthread_mutex_unlock(&info->append_buffer_lock);
#endif
  return res;
}

my_off_t my_b_safe_tell(IO_CACHE *info)
{
  if (unlikely(info->type == SEQ_READ_APPEND))
    return my_b_append_tell(info);
  return my_b_tell(info);
}

/*
  Make next read happen at the given position
  For write cache, make next write happen at the given position
*/

void my_b_seek(IO_CACHE *info,my_off_t pos)
{
  my_off_t offset;
  DBUG_ENTER("my_b_seek");
  DBUG_PRINT("enter",("pos: %lu", (ulong) pos));

  /*
    TODO:
       Verify that it is OK to do seek in the non-append
       area in SEQ_READ_APPEND cache
     a) see if this always works
     b) see if there is a better way to make it work
  */
  if (info->type == SEQ_READ_APPEND)
    VOID(flush_io_cache(info));

  offset=(pos - info->pos_in_file);

  if (info->type == READ_CACHE || info->type == SEQ_READ_APPEND)
  {
    /* TODO: explain why this works if pos < info->pos_in_file */
    if ((ulonglong) offset < (ulonglong) (info->read_end - info->buffer))
    {
      /* The read is in the current buffer; Reuse it */
      info->read_pos = info->buffer + offset;
      DBUG_VOID_RETURN;
    }
    else
    {
      /* Force a new read on next my_b_read */
      info->read_pos=info->read_end=info->buffer;
    }
  }
  else if (info->type == WRITE_CACHE)
  {
    /* If write is in current buffer, reuse it */
    if ((ulonglong) offset <
	(ulonglong) (info->write_end - info->write_buffer))
    {
      info->write_pos = info->write_buffer + offset;
      DBUG_VOID_RETURN;
    }
    VOID(flush_io_cache(info));
    /* Correct buffer end so that we write in increments of IO_SIZE */
    info->write_end=(info->write_buffer+info->buffer_length-
		     (pos & (IO_SIZE-1)));
  }
  info->pos_in_file=pos;
  info->seek_not_done=1;
  DBUG_VOID_RETURN;
}


/*
  Fill buffer.  Note that this assumes that you have already used
  all characters in the CACHE, independent of the read_pos value!
  return:  0 on error or EOF (info->error = -1 on error)
  number of characters
*/

uint my_b_fill(IO_CACHE *info)
{
  my_off_t pos_in_file=(info->pos_in_file+
			(uint) (info->read_end - info->buffer));
  my_off_t max_length;
  uint diff_length,length;
  if (info->seek_not_done)
  {					/* File touched, do seek */
    if (my_seek(info->file,pos_in_file,MY_SEEK_SET,MYF(0)) ==
	MY_FILEPOS_ERROR)
    {
      info->error= 0;
      return 0;
    }
    info->seek_not_done=0;
  }
  diff_length=(uint) (pos_in_file & (IO_SIZE-1));
  max_length= (my_off_t) (info->end_of_file - pos_in_file);
  if (max_length > (my_off_t) (info->read_length-diff_length))
    max_length=(my_off_t) (info->read_length-diff_length);
  if (!max_length)
  {
    info->error= 0;
    return 0;					/* EOF */
  }
   else if ((length=my_read(info->file,info->buffer,(uint) max_length,
			   info->myflags)) == (uint) -1)
  {
    info->error= -1;
    return 0;
  }
  info->read_pos=info->buffer;
  info->read_end=info->buffer+length;
  info->pos_in_file=pos_in_file;
  return length;
}


/*
  Read a string ended by '\n' into a buffer of 'max_length' size.
  Returns number of characters read, 0 on error.
  last byte is set to '\0'
  If buffer is full then to[max_length-1] will be set to \0.
*/

uint my_b_gets(IO_CACHE *info, char *to, uint max_length)
{
  char *start = to;
  uint length;
  max_length--;					/* Save place for end \0 */
  /* Calculate number of characters in buffer */
  if (!(length= my_b_bytes_in_cache(info)) &&
      !(length= my_b_fill(info)))
    return 0;
  for (;;)
  {
    char *pos,*end;
    if (length > max_length)
      length=max_length;
    for (pos=info->read_pos,end=pos+length ; pos < end ;)
    {
      if ((*to++ = *pos++) == '\n')
      {
	info->read_pos=pos;
	*to='\0';
	return (uint) (to-start);
      }
    }
    if (!(max_length-=length))
    {
     /* Found enough charcters;  Return found string */
      info->read_pos=pos;
      *to='\0';
      return (uint) (to-start);
    }
    if (!(length=my_b_fill(info)))
      return 0;
  }
}


my_off_t my_b_filelength(IO_CACHE *info)
{
  if (info->type == WRITE_CACHE)
  {
    return my_b_tell(info);
  }
  else
  {
    info->seek_not_done=1;
    return my_seek(info->file,0L,MY_SEEK_END,MYF(0));
  }
}


/*
  Simple printf version.  Supports '%s', '%d', '%u', "%ld" and "%lu"
  Used for logging in MySQL
  returns number of written character, or (uint) -1 on error
*/

uint my_b_printf(IO_CACHE *info, const char* fmt, ...)
{
  int result;
  va_list args;
  va_start(args,fmt);
  result=my_b_vprintf(info, fmt, args);
  va_end(args);
  return result;
}


uint my_b_vprintf(IO_CACHE *info, const char* fmt, va_list args)
{
  uint out_length=0;
  uint minimum_width; /* as yet unimplemented */
  uint minimum_width_sign;
  uint precision; /* as yet unimplemented for anything but %b */

  /*
    Store the location of the beginning of a format directive, for the
    case where we learn we shouldn't have been parsing a format string
    at all, and we don't want to lose the flag/precision/width/size
    information.
   */
  const char* backtrack;

  for (; *fmt != '\0'; fmt++)
  {
    /* Copy everything until '%' or end of string */
    const char *start=fmt;
    uint length;
    
    for (; (*fmt != '\0') && (*fmt != '%'); fmt++) ;

    length= (uint) (fmt - start);
    out_length+=length;
    if (my_b_write(info, start, length))
      goto err;

    if (*fmt == '\0')				/* End of format */
    {
      return out_length;
    }

    /* 
      By this point, *fmt must be a percent;  Keep track of this location and
      skip over the percent character. 
    */
    DBUG_ASSERT(*fmt == '%');
    backtrack= fmt;
    fmt++;

    minimum_width= 0;
    precision= 0;
    minimum_width_sign= 1;
    /* Skip if max size is used (to be compatible with printf) */
    while (*fmt == '-') { fmt++; minimum_width_sign= -1; }
    if (*fmt == '*') {
      precision= (int) va_arg(args, int);
      fmt++;
    } else {
      while (my_isdigit(&my_charset_latin1, *fmt)) {
        minimum_width=(minimum_width * 10) + (*fmt - '0');
        fmt++;
      }
    }
    minimum_width*= minimum_width_sign;

    if (*fmt == '.') {
      fmt++;
      if (*fmt == '*') {
        precision= (int) va_arg(args, int);
        fmt++;
      } else {
        while (my_isdigit(&my_charset_latin1, *fmt)) {
          precision=(precision * 10) + (*fmt - '0');
          fmt++;
        }
      }
    }

    if (*fmt == 's')				/* String parameter */
    {
      reg2 char *par = va_arg(args, char *);
      uint length = (uint) strlen(par);
      /* TODO: implement minimum width and precision */
      out_length+=length;
      if (my_b_write(info, par, length))
	goto err;
    }
    else if (*fmt == 'b')                       /* Sized buffer parameter, only precision makes sense */
    {
      char *par = va_arg(args, char *);
      out_length+= precision;
      if (my_b_write(info, par, precision))
        goto err;
    }
    else if (*fmt == 'd' || *fmt == 'u')	/* Integer parameter */
    {
      register int iarg;
      uint length;
      char buff[17];

      iarg = va_arg(args, int);
      if (*fmt == 'd')
	length= (uint) (int10_to_str((long) iarg,buff, -10) - buff);
      else
	length= (uint) (int10_to_str((long) (uint) iarg,buff,10)- buff);
      out_length+=length;
      if (my_b_write(info, buff, length))
	goto err;
    }
    else if ((*fmt == 'l' && fmt[1] == 'd') || fmt[1] == 'u')
      /* long parameter */
    {
      register long iarg;
      uint length;
      char buff[17];

      iarg = va_arg(args, long);
      if (*++fmt == 'd')
	length= (uint) (int10_to_str(iarg,buff, -10) - buff);
      else
	length= (uint) (int10_to_str(iarg,buff,10)- buff);
      out_length+=length;
      if (my_b_write(info, buff, length))
	goto err;
    }
    else
    {
      /* %% or unknown code */
      if (my_b_write(info, backtrack, fmt-backtrack))
        goto err;
      out_length+= fmt-backtrack;
    }
  }
  return out_length;

err:
  return (uint) -1;
}