summaryrefslogtreecommitdiff
path: root/subversion/libsvn_ra_serf/options.c
blob: a52977bbf1f89c33ff81dc85dd304ef874bf9ebe (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
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
/*
 * options.c :  entry point for OPTIONS RA functions for ra_serf
 *
 * ====================================================================
 *    Licensed to the Apache Software Foundation (ASF) under one
 *    or more contributor license agreements.  See the NOTICE file
 *    distributed with this work for additional information
 *    regarding copyright ownership.  The ASF licenses this file
 *    to you under the Apache License, Version 2.0 (the
 *    "License"); you may not use this file except in compliance
 *    with the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing,
 *    software distributed under the License is distributed on an
 *    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *    KIND, either express or implied.  See the License for the
 *    specific language governing permissions and limitations
 *    under the License.
 * ====================================================================
 */



#include <apr_uri.h>

#include <serf.h>

#include "svn_dirent_uri.h"
#include "svn_hash.h"
#include "svn_pools.h"
#include "svn_path.h"
#include "svn_ra.h"
#include "svn_dav.h"
#include "svn_xml.h"
#include "svn_ctype.h"

#include "../libsvn_ra/ra_loader.h"
#include "svn_private_config.h"
#include "private/svn_fspath.h"

#include "ra_serf.h"


/* In a debug build, setting this environment variable to "yes" will force
   the client to speak v1, even if the server is capable of speaking v2. */
#define SVN_IGNORE_V2_ENV_VAR "SVN_I_LIKE_LATENCY_SO_IGNORE_HTTPV2"


/*
 * This enum represents the current state of our XML parsing for an OPTIONS.
 */
enum options_state_e {
  INITIAL = XML_STATE_INITIAL,
  OPTIONS,
  ACTIVITY_COLLECTION,
  HREF
};

typedef struct options_context_t {
  /* pool to allocate memory from */
  apr_pool_t *pool;

  /* Have we extracted options values from the headers already?  */
  svn_boolean_t headers_processed;

  svn_ra_serf__session_t *session;
  svn_ra_serf__handler_t *handler;

  svn_ra_serf__response_handler_t inner_handler;
  void *inner_baton;

  const char *activity_collection;
  svn_revnum_t youngest_rev;

} options_context_t;

#define D_ "DAV:"
#define S_ SVN_XML_NAMESPACE
static const svn_ra_serf__xml_transition_t options_ttable[] = {
  { INITIAL, D_, "options-response", OPTIONS,
    FALSE, { NULL }, FALSE },

  { OPTIONS, D_, "activity-collection-set", ACTIVITY_COLLECTION,
    FALSE, { NULL }, FALSE },

  { ACTIVITY_COLLECTION, D_, "href", HREF,
    TRUE, { NULL }, TRUE },

  { 0 }
};


/* Conforms to svn_ra_serf__xml_closed_t  */
static svn_error_t *
options_closed(svn_ra_serf__xml_estate_t *xes,
               void *baton,
               int leaving_state,
               const svn_string_t *cdata,
               apr_hash_t *attrs,
               apr_pool_t *scratch_pool)
{
  options_context_t *opt_ctx = baton;

  SVN_ERR_ASSERT(leaving_state == HREF);
  SVN_ERR_ASSERT(cdata != NULL);

  opt_ctx->activity_collection = svn_urlpath__canonicalize(cdata->data,
                                                           opt_ctx->pool);

  return SVN_NO_ERROR;
}

/* Implements svn_ra_serf__request_body_delegate_t */
static svn_error_t *
create_options_body(serf_bucket_t **body_bkt,
                    void *baton,
                    serf_bucket_alloc_t *alloc,
                    apr_pool_t *pool /* request pool */,
                    apr_pool_t *scratch_pool)
{
  serf_bucket_t *body;
  body = serf_bucket_aggregate_create(alloc);
  svn_ra_serf__add_xml_header_buckets(body, alloc);
  svn_ra_serf__add_open_tag_buckets(body, alloc, "D:options",
                                    "xmlns:D", "DAV:",
                                    SVN_VA_NULL);
  svn_ra_serf__add_tag_buckets(body, "D:activity-collection-set", NULL, alloc);
  svn_ra_serf__add_close_tag_buckets(body, alloc, "D:options");

  *body_bkt = body;
  return SVN_NO_ERROR;
}


/* We use these static pointers so we can employ pointer comparison
 * of our capabilities hash members instead of strcmp()ing all over
 * the place.
 */
/* Both server and repository support the capability. */
static const char *const capability_yes = "yes";
/* Either server or repository does not support the capability. */
static const char *const capability_no = "no";
/* Server supports the capability, but don't yet know if repository does. */
static const char *const capability_server_yes = "server-yes";


/* This implements serf_bucket_headers_do_callback_fn_t.
 */
static int
capabilities_headers_iterator_callback(void *baton,
                                       const char *key,
                                       const char *val)
{
  options_context_t *opt_ctx = baton;
  svn_ra_serf__session_t *session = opt_ctx->session;

  if (svn_cstring_casecmp(key, "dav") == 0)
    {
      /* Each header may contain multiple values, separated by commas, e.g.:
           DAV: version-control,checkout,working-resource
           DAV: merge,baseline,activity,version-controlled-collection
           DAV: http://subversion.tigris.org/xmlns/dav/svn/depth */
      apr_array_header_t *vals = svn_cstring_split(val, ",", TRUE,
                                                   opt_ctx->pool);

      /* Right now we only have a few capabilities to detect, so just
         seek for them directly.  This could be written slightly more
         efficiently, but that wouldn't be worth it until we have many
         more capabilities. */

      if (svn_cstring_match_list(SVN_DAV_NS_DAV_SVN_DEPTH, vals))
        {
          svn_hash_sets(session->capabilities,
                        SVN_RA_CAPABILITY_DEPTH, capability_yes);
        }
      if (svn_cstring_match_list(SVN_DAV_NS_DAV_SVN_MERGEINFO, vals))
        {
          /* The server doesn't know what repository we're referring
             to, so it can't just say capability_yes. */
          if (!svn_hash_gets(session->capabilities,
                             SVN_RA_CAPABILITY_MERGEINFO))
            {
              svn_hash_sets(session->capabilities, SVN_RA_CAPABILITY_MERGEINFO,
                            capability_server_yes);
            }
        }
      if (svn_cstring_match_list(SVN_DAV_NS_DAV_SVN_LOG_REVPROPS, vals))
        {
          svn_hash_sets(session->capabilities,
                        SVN_RA_CAPABILITY_LOG_REVPROPS, capability_yes);
        }
      if (svn_cstring_match_list(SVN_DAV_NS_DAV_SVN_ATOMIC_REVPROPS, vals))
        {
          svn_hash_sets(session->capabilities,
                        SVN_RA_CAPABILITY_ATOMIC_REVPROPS, capability_yes);
        }
      if (svn_cstring_match_list(SVN_DAV_NS_DAV_SVN_PARTIAL_REPLAY, vals))
        {
          svn_hash_sets(session->capabilities,
                        SVN_RA_CAPABILITY_PARTIAL_REPLAY, capability_yes);
        }
      if (svn_cstring_match_list(SVN_DAV_NS_DAV_SVN_INHERITED_PROPS, vals))
        {
          svn_hash_sets(session->capabilities,
                        SVN_RA_CAPABILITY_INHERITED_PROPS, capability_yes);
        }
      if (svn_cstring_match_list(SVN_DAV_NS_DAV_SVN_REVERSE_FILE_REVS,
                                 vals))
        {
          svn_hash_sets(session->capabilities,
                        SVN_RA_CAPABILITY_GET_FILE_REVS_REVERSE,
                        capability_yes);
        }
      if (svn_cstring_match_list(SVN_DAV_NS_DAV_SVN_EPHEMERAL_TXNPROPS, vals))
        {
          svn_hash_sets(session->capabilities,
                        SVN_RA_CAPABILITY_EPHEMERAL_TXNPROPS, capability_yes);
        }
      if (svn_cstring_match_list(SVN_DAV_NS_DAV_SVN_INLINE_PROPS, vals))
        {
          session->supports_inline_props = TRUE;
        }
      if (svn_cstring_match_list(SVN_DAV_NS_DAV_SVN_REPLAY_REV_RESOURCE, vals))
        {
          session->supports_rev_rsrc_replay = TRUE;
        }
    }

  /* SVN-specific headers -- if present, server supports HTTP protocol v2 */
  else if (!svn_ctype_casecmp(key[0], 'S')
           && !svn_ctype_casecmp(key[1], 'V')
           && !svn_ctype_casecmp(key[2], 'N'))
    {
      /* If we've not yet seen any information about supported POST
         requests, we'll initialize the list/hash with "create-txn"
         (which we know is supported by virtue of the server speaking
         HTTPv2 at all. */
      if (! session->supported_posts)
        {
          session->supported_posts = apr_hash_make(session->pool);
          apr_hash_set(session->supported_posts, "create-txn", 10, (void *)1);
        }

      if (svn_cstring_casecmp(key, SVN_DAV_ROOT_URI_HEADER) == 0)
        {
          session->repos_root = session->session_url;
          session->repos_root.path =
            (char *)svn_fspath__canonicalize(val, session->pool);
          session->repos_root_str =
            svn_urlpath__canonicalize(
                apr_uri_unparse(session->pool, &session->repos_root, 0),
                session->pool);
        }
      else if (svn_cstring_casecmp(key, SVN_DAV_ME_RESOURCE_HEADER) == 0)
        {
#ifdef SVN_DEBUG
          char *ignore_v2_env_var = getenv(SVN_IGNORE_V2_ENV_VAR);

          if (!(ignore_v2_env_var
                && apr_strnatcasecmp(ignore_v2_env_var, "yes") == 0))
            session->me_resource = apr_pstrdup(session->pool, val);
#else
          session->me_resource = apr_pstrdup(session->pool, val);
#endif
        }
      else if (svn_cstring_casecmp(key, SVN_DAV_REV_STUB_HEADER) == 0)
        {
          session->rev_stub = apr_pstrdup(session->pool, val);
        }
      else if (svn_cstring_casecmp(key, SVN_DAV_REV_ROOT_STUB_HEADER) == 0)
        {
          session->rev_root_stub = apr_pstrdup(session->pool, val);
        }
      else if (svn_cstring_casecmp(key, SVN_DAV_TXN_STUB_HEADER) == 0)
        {
          session->txn_stub = apr_pstrdup(session->pool, val);
        }
      else if (svn_cstring_casecmp(key, SVN_DAV_TXN_ROOT_STUB_HEADER) == 0)
        {
          session->txn_root_stub = apr_pstrdup(session->pool, val);
        }
      else if (svn_cstring_casecmp(key, SVN_DAV_VTXN_STUB_HEADER) == 0)
        {
          session->vtxn_stub = apr_pstrdup(session->pool, val);
        }
      else if (svn_cstring_casecmp(key, SVN_DAV_VTXN_ROOT_STUB_HEADER) == 0)
        {
          session->vtxn_root_stub = apr_pstrdup(session->pool, val);
        }
      else if (svn_cstring_casecmp(key, SVN_DAV_REPOS_UUID_HEADER) == 0)
        {
          session->uuid = apr_pstrdup(session->pool, val);
        }
      else if (svn_cstring_casecmp(key, SVN_DAV_YOUNGEST_REV_HEADER) == 0)
        {
          opt_ctx->youngest_rev = SVN_STR_TO_REV(val);
        }
      else if (svn_cstring_casecmp(key, SVN_DAV_ALLOW_BULK_UPDATES) == 0)
        {
          session->server_allows_bulk = apr_pstrdup(session->pool, val);
        }
      else if (svn_cstring_casecmp(key, SVN_DAV_SUPPORTED_POSTS_HEADER) == 0)
        {
          /* May contain multiple values, separated by commas. */
          int i;
          apr_array_header_t *vals = svn_cstring_split(val, ",", TRUE,
                                                       session->pool);

          for (i = 0; i < vals->nelts; i++)
            {
              const char *post_val = APR_ARRAY_IDX(vals, i, const char *);

              svn_hash_sets(session->supported_posts, post_val, (void *)1);
            }
        }
      else if (svn_cstring_casecmp(key, SVN_DAV_REPOSITORY_MERGEINFO) == 0)
        {
          if (svn_cstring_casecmp(val, "yes") == 0)
            {
              svn_hash_sets(session->capabilities, SVN_RA_CAPABILITY_MERGEINFO,
                            capability_yes);
            }
          else if (svn_cstring_casecmp(val, "no") == 0)
            {
              svn_hash_sets(session->capabilities, SVN_RA_CAPABILITY_MERGEINFO,
                            capability_no);
            }
        }
    }

  return 0;
}


/* A custom serf_response_handler_t which is mostly a wrapper around
   the expat-based response handler -- it just notices OPTIONS response
   headers first, before handing off to the xml parser.
   Implements svn_ra_serf__response_handler_t */
static svn_error_t *
options_response_handler(serf_request_t *request,
                         serf_bucket_t *response,
                         void *baton,
                         apr_pool_t *pool)
{
  options_context_t *opt_ctx = baton;

  if (!opt_ctx->headers_processed)
    {
      svn_ra_serf__session_t *session = opt_ctx->session;
      serf_bucket_t *hdrs = serf_bucket_response_get_headers(response);

      /* Start out assuming all capabilities are unsupported. */
      svn_hash_sets(session->capabilities, SVN_RA_CAPABILITY_PARTIAL_REPLAY,
                    capability_no);
      svn_hash_sets(session->capabilities, SVN_RA_CAPABILITY_DEPTH,
                    capability_no);
      svn_hash_sets(session->capabilities, SVN_RA_CAPABILITY_MERGEINFO,
                    NULL);
      svn_hash_sets(session->capabilities, SVN_RA_CAPABILITY_LOG_REVPROPS,
                    capability_no);
      svn_hash_sets(session->capabilities, SVN_RA_CAPABILITY_ATOMIC_REVPROPS,
                    capability_no);
      svn_hash_sets(session->capabilities, SVN_RA_CAPABILITY_INHERITED_PROPS,
                    capability_no);
      svn_hash_sets(session->capabilities, SVN_RA_CAPABILITY_EPHEMERAL_TXNPROPS,
                    capability_no);
      svn_hash_sets(session->capabilities, SVN_RA_CAPABILITY_GET_FILE_REVS_REVERSE,
                    capability_no);

      /* Then see which ones we can discover. */
      serf_bucket_headers_do(hdrs, capabilities_headers_iterator_callback,
                             opt_ctx);

      /* Assume mergeinfo capability unsupported, if didn't receive information
         about server or repository mergeinfo capability. */
      if (!svn_hash_gets(session->capabilities, SVN_RA_CAPABILITY_MERGEINFO))
        svn_hash_sets(session->capabilities, SVN_RA_CAPABILITY_MERGEINFO,
                      capability_no);

      opt_ctx->headers_processed = TRUE;
    }

  /* Execute the 'real' response handler to XML-parse the response body. */
  return opt_ctx->inner_handler(request, response, opt_ctx->inner_baton, pool);
}


static svn_error_t *
create_options_req(options_context_t **opt_ctx,
                   svn_ra_serf__session_t *session,
                   apr_pool_t *pool)
{
  options_context_t *new_ctx;
  svn_ra_serf__xml_context_t *xmlctx;
  svn_ra_serf__handler_t *handler;

  new_ctx = apr_pcalloc(pool, sizeof(*new_ctx));
  new_ctx->pool = pool;
  new_ctx->session = session;

  new_ctx->youngest_rev = SVN_INVALID_REVNUM;

  xmlctx = svn_ra_serf__xml_context_create(options_ttable,
                                           NULL, options_closed, NULL,
                                           new_ctx,
                                           pool);
  handler = svn_ra_serf__create_expat_handler(session, xmlctx, NULL, pool);

  handler->method = "OPTIONS";
  handler->path = session->session_url.path;
  handler->body_delegate = create_options_body;
  handler->body_type = "text/xml";

  new_ctx->handler = handler;

  new_ctx->inner_handler = handler->response_handler;
  new_ctx->inner_baton = handler->response_baton;
  handler->response_handler = options_response_handler;
  handler->response_baton = new_ctx;

  *opt_ctx = new_ctx;

  return SVN_NO_ERROR;
}


svn_error_t *
svn_ra_serf__v2_get_youngest_revnum(svn_revnum_t *youngest,
                                    svn_ra_serf__session_t *session,
                                    apr_pool_t *scratch_pool)
{
  options_context_t *opt_ctx;

  SVN_ERR_ASSERT(SVN_RA_SERF__HAVE_HTTPV2_SUPPORT(session));

  SVN_ERR(create_options_req(&opt_ctx, session, scratch_pool));
  SVN_ERR(svn_ra_serf__context_run_one(opt_ctx->handler, scratch_pool));

  if (opt_ctx->handler->sline.code != 200)
    return svn_error_trace(svn_ra_serf__unexpected_status(opt_ctx->handler));

  if (! SVN_IS_VALID_REVNUM(opt_ctx->youngest_rev))
    return svn_error_create(SVN_ERR_RA_DAV_OPTIONS_REQ_FAILED, NULL,
                            _("The OPTIONS response did not include "
                              "the youngest revision"));

  *youngest = opt_ctx->youngest_rev;

  return SVN_NO_ERROR;
}


svn_error_t *
svn_ra_serf__v1_get_activity_collection(const char **activity_url,
                                        svn_ra_serf__session_t *session,
                                        apr_pool_t *result_pool,
                                        apr_pool_t *scratch_pool)
{
  options_context_t *opt_ctx;

  SVN_ERR_ASSERT(!SVN_RA_SERF__HAVE_HTTPV2_SUPPORT(session));

  if (session->activity_collection_url)
    {
      *activity_url = apr_pstrdup(result_pool,
                                  session->activity_collection_url);
      return SVN_NO_ERROR;
    }

  SVN_ERR(create_options_req(&opt_ctx, session, scratch_pool));
  SVN_ERR(svn_ra_serf__context_run_one(opt_ctx->handler, scratch_pool));

  if (opt_ctx->handler->sline.code != 200)
    return svn_error_trace(svn_ra_serf__unexpected_status(opt_ctx->handler));

  /* Cache the result. */
  if (opt_ctx->activity_collection)
    {
      session->activity_collection_url =
                    apr_pstrdup(session->pool, opt_ctx->activity_collection);
    }
  else
    {
      return svn_error_create(SVN_ERR_RA_DAV_OPTIONS_REQ_FAILED, NULL,
                              _("The OPTIONS response did not include the "
                                "requested activity-collection-set value"));
    }

  *activity_url = apr_pstrdup(result_pool, opt_ctx->activity_collection);

  return SVN_NO_ERROR;

}



/** Capabilities exchange. */

svn_error_t *
svn_ra_serf__exchange_capabilities(svn_ra_serf__session_t *serf_sess,
                                   const char **corrected_url,
                                   apr_pool_t *result_pool,
                                   apr_pool_t *scratch_pool)
{
  options_context_t *opt_ctx;

  if (corrected_url)
    *corrected_url = NULL;

  /* This routine automatically fills in serf_sess->capabilities */
  SVN_ERR(create_options_req(&opt_ctx, serf_sess, scratch_pool));

  opt_ctx->handler->no_fail_on_http_redirect_status = TRUE;

  SVN_ERR(svn_ra_serf__context_run_one(opt_ctx->handler, scratch_pool));

  /* If our caller cares about server redirections, and our response
     carries such a thing, report as much.  We'll disregard ERR --
     it's most likely just a complaint about the response body not
     successfully parsing as XML or somesuch. */
  if (corrected_url && (opt_ctx->handler->sline.code == 301))
    {
      if (!opt_ctx->handler->location || !*opt_ctx->handler->location)
        {
          return svn_error_create(
                    SVN_ERR_RA_DAV_RESPONSE_HEADER_BADNESS, NULL,
                    _("Location header not set on redirect response"));
        }
      else if (svn_path_is_url(opt_ctx->handler->location))
        {
          *corrected_url = svn_uri_canonicalize(opt_ctx->handler->location,
                                                result_pool);
        }
      else
        {
          /* RFC1945 and RFC2616 state that the Location header's value
             (from whence this CORRECTED_URL comes), if present, must be an
             absolute URI.  But some Apache versions (those older than 2.2.11,
             it seems) transmit only the path portion of the URI.
             See issue #3775 for details. */

          apr_uri_t corrected_URI = serf_sess->session_url;

          corrected_URI.path = (char *)corrected_url;
          *corrected_url = svn_uri_canonicalize(
                              apr_uri_unparse(scratch_pool, &corrected_URI, 0),
                              result_pool);
        }

      return SVN_NO_ERROR;
    }
  else if (opt_ctx->handler->sline.code >= 300
           && opt_ctx->handler->sline.code < 399)
    {
      return svn_error_createf(SVN_ERR_RA_SESSION_URL_MISMATCH, NULL,
                               (opt_ctx->handler->sline.code == 301
                                ? _("Repository moved permanently to '%s'")
                                : _("Repository moved temporarily to '%s'")),
                              opt_ctx->handler->location);
    }

  if (opt_ctx->handler->sline.code != 200)
    return svn_error_trace(svn_ra_serf__unexpected_status(opt_ctx->handler));

  /* Opportunistically cache any reported activity URL.  (We don't
     want to have to ask for this again later, potentially against an
     unreadable commit anchor URL.)  */
  if (opt_ctx->activity_collection)
    {
      serf_sess->activity_collection_url =
        apr_pstrdup(serf_sess->pool, opt_ctx->activity_collection);
    }

  return SVN_NO_ERROR;
}

/* Implements svn_ra_serf__request_body_delegate_t */
static svn_error_t *
create_simple_options_body(serf_bucket_t **body_bkt,
                           void *baton,
                           serf_bucket_alloc_t *alloc,
                           apr_pool_t *pool /* request pool */,
                           apr_pool_t *scratch_pool)
{
  serf_bucket_t *body;
  serf_bucket_t *s;

  body = serf_bucket_aggregate_create(alloc);
  svn_ra_serf__add_xml_header_buckets(body, alloc);

  s = SERF_BUCKET_SIMPLE_STRING("<D:options xmlns:D=\"DAV:\" />", alloc);
  serf_bucket_aggregate_append(body, s);

  *body_bkt = body;
  return SVN_NO_ERROR;
}


svn_error_t *
svn_ra_serf__probe_proxy(svn_ra_serf__session_t *serf_sess,
                         apr_pool_t *scratch_pool)
{
  svn_ra_serf__handler_t *handler;

  handler = svn_ra_serf__create_handler(serf_sess, scratch_pool);
  handler->method = "OPTIONS";
  handler->path = serf_sess->session_url.path;

  /* We don't care about the response body, so discard it.  */
  handler->response_handler = svn_ra_serf__handle_discard_body;

  /* We need a simple body, in order to send it in chunked format.  */
  handler->body_delegate = create_simple_options_body;
  handler->no_fail_on_http_failure_status = TRUE;

  /* No special headers.  */

  SVN_ERR(svn_ra_serf__context_run_one(handler, scratch_pool));
  /* Some versions of nginx in reverse proxy mode will return 411. They want
     a Content-Length header, rather than chunked requests. We can keep other
     HTTP/1.1 features, but will disable the chunking.  */
  if (handler->sline.code == 411)
    {
      serf_sess->using_chunked_requests = FALSE;

      return SVN_NO_ERROR;
    }
  if (handler->sline.code != 200)
    SVN_ERR(svn_ra_serf__unexpected_status(handler));

  return SVN_NO_ERROR;
}


svn_error_t *
svn_ra_serf__has_capability(svn_ra_session_t *ra_session,
                            svn_boolean_t *has,
                            const char *capability,
                            apr_pool_t *pool)
{
  svn_ra_serf__session_t *serf_sess = ra_session->priv;
  const char *cap_result;

  /* This capability doesn't rely on anything server side. */
  if (strcmp(capability, SVN_RA_CAPABILITY_COMMIT_REVPROPS) == 0)
    {
      *has = TRUE;
      return SVN_NO_ERROR;
    }

  cap_result = svn_hash_gets(serf_sess->capabilities, capability);

  /* If any capability is unknown, they're all unknown, so ask. */
  if (cap_result == NULL)
    SVN_ERR(svn_ra_serf__exchange_capabilities(serf_sess, NULL, pool, pool));

  /* Try again, now that we've fetched the capabilities. */
  cap_result = svn_hash_gets(serf_sess->capabilities, capability);

  /* Some capabilities depend on the repository as well as the server. */
  if (cap_result == capability_server_yes)
    {
      if (strcmp(capability, SVN_RA_CAPABILITY_MERGEINFO) == 0)
        {
          /* Handle mergeinfo specially.  Mergeinfo depends on the
             repository as well as the server, but the server routine
             that answered our svn_ra_serf__exchange_capabilities() call above
             didn't even know which repository we were interested in
             -- it just told us whether the server supports mergeinfo.
             If the answer was 'no', there's no point checking the
             particular repository; but if it was 'yes', we still must
             change it to 'no' iff the repository itself doesn't
             support mergeinfo. */
          svn_mergeinfo_catalog_t ignored;
          svn_error_t *err;
          apr_array_header_t *paths = apr_array_make(pool, 1,
                                                     sizeof(char *));
          APR_ARRAY_PUSH(paths, const char *) = "";

          err = svn_ra_serf__get_mergeinfo(ra_session, &ignored, paths, 0,
                                           svn_mergeinfo_explicit,
                                           FALSE /* include_descendants */,
                                           pool);

          if (err)
            {
              if (err->apr_err == SVN_ERR_UNSUPPORTED_FEATURE)
                {
                  svn_error_clear(err);
                  cap_result = capability_no;
                }
              else if (err->apr_err == SVN_ERR_FS_NOT_FOUND)
                {
                  /* Mergeinfo requests use relative paths, and
                     anyway we're in r0, so this is a likely error,
                     but it means the repository supports mergeinfo! */
                  svn_error_clear(err);
                  cap_result = capability_yes;
                }
              else
                return svn_error_trace(err);
            }
          else
            cap_result = capability_yes;

          svn_hash_sets(serf_sess->capabilities,
                        SVN_RA_CAPABILITY_MERGEINFO,  cap_result);
        }
      else
        {
          return svn_error_createf
            (SVN_ERR_UNKNOWN_CAPABILITY, NULL,
             _("Don't know how to handle '%s' for capability '%s'"),
             capability_server_yes, capability);
        }
    }

  if (cap_result == capability_yes)
    {
      *has = TRUE;
    }
  else if (cap_result == capability_no)
    {
      *has = FALSE;
    }
  else if (cap_result == NULL)
    {
      return svn_error_createf
        (SVN_ERR_UNKNOWN_CAPABILITY, NULL,
         _("Don't know anything about capability '%s'"), capability);
    }
  else  /* "can't happen" */
    {
      /* Well, let's hope it's a string. */
      return svn_error_createf
        (SVN_ERR_RA_DAV_OPTIONS_REQ_FAILED, NULL,
         _("Attempt to fetch capability '%s' resulted in '%s'"),
         capability, cap_result);
    }

  return SVN_NO_ERROR;
}