stream.c

subversion-1.4.3-1.tar.gz 配置svn的源码

/*
 * stream.c:   svn_stream operations
 *
 * ====================================================================
 * Copyright (c) 2000-2004, 2006 CollabNet.  All rights reserved.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution.  The terms
 * are also available at http://subversion.tigris.org/license-1.html.
 * If newer versions of this license are posted there, you may use a
 * newer version instead, at your option.
 *
 * This software consists of voluntary contributions made by many
 * individuals.  For exact contribution history, see the revision
 * history and logs, available at http://subversion.tigris.org/.
 * ====================================================================
 */

#include "svn_private_config.h"

#include <assert.h>
#include <stdio.h>

#include <apr.h>
#include <apr_pools.h>
#include <apr_strings.h>
#include <apr_file_io.h>
#include <apr_errno.h>
#include <apr_md5.h>

#ifdef SVN_HAVE_ZLIB
#include <zlib.h>
#endif

#include "svn_pools.h"
#include "svn_io.h"
#include "svn_error.h"
#include "svn_string.h"
#include "svn_utf.h"


struct svn_stream_t {
  void *baton;
  svn_read_fn_t read_fn;
  svn_write_fn_t write_fn;
  svn_close_fn_t close_fn;
};



/*** Generic streams. ***/

svn_stream_t *
svn_stream_create(void *baton, apr_pool_t *pool)
{
  svn_stream_t *stream;

  stream = apr_palloc(pool, sizeof(*stream));
  stream->baton = baton;
  stream->read_fn = NULL;
  stream->write_fn = NULL;
  stream->close_fn = NULL;
  return stream;
}


void
svn_stream_set_baton(svn_stream_t *stream, void *baton)
{
  stream->baton = baton;
}


void
svn_stream_set_read(svn_stream_t *stream, svn_read_fn_t read_fn)
{
  stream->read_fn = read_fn;
}


void
svn_stream_set_write(svn_stream_t *stream, svn_write_fn_t write_fn)
{
  stream->write_fn = write_fn;
}


void
svn_stream_set_close(svn_stream_t *stream, svn_close_fn_t close_fn)
{
  stream->close_fn = close_fn;
}


svn_error_t *
svn_stream_read(svn_stream_t *stream, char *buffer, apr_size_t *len)
{
  assert(stream->read_fn != NULL);
  return stream->read_fn(stream->baton, buffer, len);
}


svn_error_t *
svn_stream_write(svn_stream_t *stream, const char *data, apr_size_t *len)
{
  assert(stream->write_fn != NULL);
  return stream->write_fn(stream->baton, data, len);
}


svn_error_t *
svn_stream_close(svn_stream_t *stream)
{
  if (stream->close_fn == NULL)
    return SVN_NO_ERROR;
  return stream->close_fn(stream->baton);
}


svn_error_t *
svn_stream_printf(svn_stream_t *stream,
                  apr_pool_t *pool,
                  const char *fmt,
                  ...)
{
  const char *message;
  va_list ap;
  apr_size_t len;

  va_start(ap, fmt);
  message = apr_pvsprintf(pool, fmt, ap);
  va_end(ap);
  
  len = strlen(message);
  return svn_stream_write(stream, message, &len);
}


svn_error_t *
svn_stream_printf_from_utf8(svn_stream_t *stream,
                            const char *encoding,
                            apr_pool_t *pool,
                            const char *fmt,
                            ...)
{
  const char *message, *translated;
  va_list ap;
  apr_size_t len;

  va_start(ap, fmt);
  message = apr_pvsprintf(pool, fmt, ap);
  va_end(ap);

  SVN_ERR(svn_utf_cstring_from_utf8_ex2(&translated, message, encoding,
                                        pool));
  
  len = strlen(translated);

  return svn_stream_write(stream, translated, &len);
}


svn_error_t *
svn_stream_readline(svn_stream_t *stream,
                    svn_stringbuf_t **stringbuf,
                    const char *eol,
                    svn_boolean_t *eof,
                    apr_pool_t *pool)
{
  apr_size_t numbytes;
  const char *match;
  char c;
  svn_stringbuf_t *str = svn_stringbuf_create("", pool);

  /* Since we're reading one character at a time, let's at least
     optimize for the 90% case.  90% of the time, we can avoid the
     stringbuf ever having to realloc() itself if we start it out at
     80 chars.  */
  svn_stringbuf_ensure(str, 80);

  match = eol;
  while (*match)
    {
      numbytes = 1;
      SVN_ERR(svn_stream_read(stream, &c, &numbytes));
      if (numbytes != 1)
        {
          /* a 'short' read means the stream has run out. */
          *eof = TRUE;
          *stringbuf = str;
          return SVN_NO_ERROR;
        }

      if (c == *match)
        match++;
      else
        match = eol;

      svn_stringbuf_appendbytes(str, &c, 1);
    }

  *eof = FALSE;
  svn_stringbuf_chop(str, match - eol);
  *stringbuf = str;
  return SVN_NO_ERROR;
}


svn_error_t *svn_stream_copy(svn_stream_t *from, svn_stream_t *to,
                             apr_pool_t *pool)
{
  char *buf = apr_palloc(pool, SVN__STREAM_CHUNK_SIZE);
  apr_size_t len;

  /* Read and write chunks until we get a short read, indicating the
     end of the stream.  (We can't get a short write without an
     associated error.) */
  while (1)
    {
      len = SVN__STREAM_CHUNK_SIZE;
      SVN_ERR(svn_stream_read(from, buf, &len));
      if (len > 0)
        SVN_ERR(svn_stream_write(to, buf, &len));
      if (len != SVN__STREAM_CHUNK_SIZE)
        break;
    }
  return SVN_NO_ERROR;
}


svn_error_t *
svn_stream_contents_same(svn_boolean_t *same,
                         svn_stream_t *stream1,
                         svn_stream_t *stream2,
                         apr_pool_t *pool)
{
  char *buf1 = apr_palloc(pool, SVN__STREAM_CHUNK_SIZE);
  char *buf2 = apr_palloc(pool, SVN__STREAM_CHUNK_SIZE);
  apr_size_t bytes_read1 = SVN__STREAM_CHUNK_SIZE;
  apr_size_t bytes_read2 = SVN__STREAM_CHUNK_SIZE;
  
  *same = TRUE;  /* assume TRUE, until disproved below */
  while (bytes_read1 == SVN__STREAM_CHUNK_SIZE
         && bytes_read2 == SVN__STREAM_CHUNK_SIZE)
    {
      SVN_ERR(svn_stream_read(stream1, buf1, &bytes_read1));
      SVN_ERR(svn_stream_read(stream2, buf2, &bytes_read2));
      
      if ((bytes_read1 != bytes_read2)
          || (memcmp(buf1, buf2, bytes_read1)))
        {
          *same = FALSE;
          break;
        }
    }

  return SVN_NO_ERROR;
}



/*** Generic readable empty stream ***/

static svn_error_t *
read_handler_empty(void *baton, char *buffer, apr_size_t *len)
{
  *len = 0;
  return SVN_NO_ERROR;
}


static svn_error_t *
write_handler_empty(void *baton, const char *data, apr_size_t *len)
{
  return SVN_NO_ERROR;
}


svn_stream_t *
svn_stream_empty(apr_pool_t *pool)
{
  svn_stream_t *stream;

  stream = svn_stream_create(NULL, pool);
  svn_stream_set_read(stream, read_handler_empty);
  svn_stream_set_write(stream, write_handler_empty);
  return stream;
}




/*** Ownership detaching stream ***/

static svn_error_t *
read_handler_disown(void *baton, char *buffer, apr_size_t *len)
{
  return svn_stream_read((svn_stream_t *)baton, buffer, len);
}

static svn_error_t *
write_handler_disown(void *baton, const char *buffer, apr_size_t *len)
{
  return svn_stream_write((svn_stream_t *)baton, buffer, len);
}


svn_stream_t *
svn_stream_disown(svn_stream_t *stream, apr_pool_t *pool)
{
  svn_stream_t *s = svn_stream_create(stream, pool);

  svn_stream_set_read(s, read_handler_disown);
  svn_stream_set_write(s, write_handler_disown);

  return s;
}



/*** Generic stream for APR files ***/
struct baton_apr {
  apr_file_t *file;
  apr_pool_t *pool;
};


static svn_error_t *
read_handler_apr(void *baton, char *buffer, apr_size_t *len)
{
  struct baton_apr *btn = baton;
  svn_error_t *err;

  err = svn_io_file_read_full(btn->file, buffer, *len, len, btn->pool);
  if (err && APR_STATUS_IS_EOF(err->apr_err))
    {
      svn_error_clear(err);
      err = SVN_NO_ERROR;
    }

  return err;
}


static svn_error_t *
write_handler_apr(void *baton, const char *data, apr_size_t *len)
{
  struct baton_apr *btn = baton;

  return svn_io_file_write_full(btn->file, data, *len, len, btn->pool);
}

static svn_error_t *
close_handler_apr(void *baton)
{
  struct baton_apr *btn = baton;

  return svn_io_file_close(btn->file, btn->pool);
}


svn_stream_t *
svn_stream_from_aprfile2(apr_file_t *file,
                         svn_boolean_t disown,
                         apr_pool_t *pool)
{
  struct baton_apr *baton;
  svn_stream_t *stream;

  if (file == NULL)
    return svn_stream_empty(pool);

  baton = apr_palloc(pool, sizeof(*baton));
  baton->file = file;
  baton->pool = pool;
  stream = svn_stream_create(baton, pool);
  svn_stream_set_read(stream, read_handler_apr);
  svn_stream_set_write(stream, write_handler_apr);

  if (! disown)
    svn_stream_set_close(stream, close_handler_apr);

  return stream;
}

svn_stream_t *
svn_stream_from_aprfile(apr_file_t *file, apr_pool_t *pool)
{
  return svn_stream_from_aprfile2(file, TRUE, pool);
}



/* Compressed stream support */

#ifdef SVN_HAVE_ZLIB

#define ZBUFFER_SIZE 4096       /* The size of the buffer the
                                   compressed stream uses to read from
                                   the substream. Basically an
                                   arbitrary value, picked to be about
                                   page-sized. */

struct zbaton {
  z_stream *in;                 /* compressed stream for reading */
  z_stream *out;                /* compressed stream for writing */
  svn_read_fn_t read;           /* substream's read function */
  svn_write_fn_t write;         /* substream's write function */
  svn_close_fn_t close;         /* substream's close function */
  void *read_buffer;            /* buffer   used   for  reading   from
                                   substream */
  int read_flush;               /* what flush mode to use while
                                   reading */
  apr_pool_t *pool;             /* The pool this baton is allocated
                                   on */
  void *subbaton;               /* The substream's baton */
};

/* zlib alloc function. opaque is the pool we need. */
static voidpf
zalloc(voidpf opaque, uInt items, uInt size)
{
  apr_pool_t *pool = opaque;
  
  return apr_palloc(pool, items * size);
}

/* zlib free function */
static void
zfree(voidpf opaque, voidpf address)
{
  /* Empty, since we allocate on the pool */
}

/* Converts a zlib error to an svn_error_t. zerr is the error code,
   function is the function name, and stream is the z_stream we are
   using.  */
static svn_error_t *
zerr_to_svn_error(int zerr, const char *function, z_stream *stream)
{
  apr_status_t status;
  const char *message;

  if (zerr == Z_OK)