src/crlf.c

   1 /*
   2  * Copyright (C) the libgit2 contributors. All rights reserved.
   3  *
   4  * This file is part of libgit2, distributed under the GNU GPL v2 with
   5  * a Linking Exception. For full terms see the included COPYING file.
   6  */
   7
   8 #include "git2/attr.h"
   9 #include "git2/blob.h"
  10 #include "git2/index.h"
  11 #include "git2/sys/filter.h"
  12
  13 #include "common.h"
  14 #include "fileops.h"
  15 #include "hash.h"
  16 #include "filter.h"
  17 #include "buf_text.h"
  18 #include "repository.h"
  19
  20 struct crlf_attrs {
  21         int crlf_action;
  22         int eol;
  23         int auto_crlf;
  24         int safe_crlf;
  25 };
  26
  27 struct crlf_filter {
  28         git_filter f;
  29 };
  30
  31 static int check_crlf(const char *value)
  32 {
  33         if (GIT_ATTR_TRUE(value))
  34                 return GIT_CRLF_TEXT;
  35
  36         if (GIT_ATTR_FALSE(value))
  37                 return GIT_CRLF_BINARY;
  38
  39         if (GIT_ATTR_UNSPECIFIED(value))
  40                 return GIT_CRLF_GUESS;
  41
  42         if (strcmp(value, "input") == 0)
  43                 return GIT_CRLF_INPUT;
  44
  45         if (strcmp(value, "auto") == 0)
  46                 return GIT_CRLF_AUTO;
  47
  48         return GIT_CRLF_GUESS;
  49 }
  50
  51 static int check_eol(const char *value)
  52 {
  53         if (GIT_ATTR_UNSPECIFIED(value))
  54                 return GIT_EOL_UNSET;
  55
  56         if (strcmp(value, "lf") == 0)
  57                 return GIT_EOL_LF;
  58
  59         if (strcmp(value, "crlf") == 0)
  60                 return GIT_EOL_CRLF;
  61
  62         return GIT_EOL_UNSET;
  63 }
  64
  65 static int crlf_input_action(struct crlf_attrs *ca)
  66 {
  67         if (ca->crlf_action == GIT_CRLF_BINARY)
  68                 return GIT_CRLF_BINARY;
  69
  70         if (ca->eol == GIT_EOL_LF)
  71                 return GIT_CRLF_INPUT;
  72
  73         if (ca->eol == GIT_EOL_CRLF)
  74                 return GIT_CRLF_CRLF;
  75
  76         return ca->crlf_action;
  77 }
  78
  79 static int has_cr_in_index(const git_filter_source *src)
  80 {
  81         git_repository *repo = git_filter_source_repo(src);
  82         const char *path = git_filter_source_path(src);
  83         git_index *index;
  84         const git_index_entry *entry;
  85         git_blob *blob;
  86         const void *blobcontent;
  87         git_off_t blobsize;
  88         bool found_cr;
  89
  90         if (!path)
  91                 return false;
  92
  93         if (git_repository_index__weakptr(&index, repo) < 0) {
  94                 giterr_clear();
  95                 return false;
  96         }
  97
  98         if (!(entry = git_index_get_bypath(index, path, 0)) &&
  99                 !(entry = git_index_get_bypath(index, path, 1)))
 100                 return false;
 101
 102         if (!S_ISREG(entry->mode)) /* don't crlf filter non-blobs */
 103                 return true;
 104
 105         if (git_blob_lookup(&blob, repo, &entry->id) < 0)
 106                 return false;
 107
 108         blobcontent = git_blob_rawcontent(blob);
 109         blobsize    = git_blob_rawsize(blob);
 110         if (!git__is_sizet(blobsize))
 111                 blobsize = (size_t)-1;
 112
 113         found_cr = (blobcontent != NULL &&
 114                 blobsize > 0 &&
 115                 memchr(blobcontent, '\r', (size_t)blobsize) != NULL);
 116
 117         git_blob_free(blob);
 118         return found_cr;
 119 }
 120
 121 static int crlf_apply_to_odb(
 122         struct crlf_attrs *ca,
 123         git_buf *to,
 124         const git_buf *from,
 125         const git_filter_source *src)
 126 {
 127         /* Empty file? Nothing to do */
 128         if (!git_buf_len(from))
 129                 return 0;
 130
 131         /* Heuristics to see if we can skip the conversion.
 132          * Straight from Core Git.
 133          */
 134         if (ca->crlf_action == GIT_CRLF_AUTO || ca->crlf_action == GIT_CRLF_GUESS) {
 135                 git_buf_text_stats stats;
 136
 137                 /* Check heuristics for binary vs text - returns true if binary */
 138                 if (git_buf_text_gather_stats(&stats, from, false))
 139                         return GIT_PASSTHROUGH;
 140
 141                 /* If there are no CR characters to filter out, then just pass */
 142                 if (!stats.cr)
 143                         return GIT_PASSTHROUGH;
 144
 145                 /* If safecrlf is enabled, sanity-check the result. */
 146                 if (stats.cr != stats.crlf || stats.lf != stats.crlf) {
 147                         switch (ca->safe_crlf) {
 148                         case GIT_SAFE_CRLF_FAIL:
 149                                 giterr_set(
 150                                         GITERR_FILTER, "LF would be replaced by CRLF in '%s'",
 151                                         git_filter_source_path(src));
 152                                 return -1;
 153                         case GIT_SAFE_CRLF_WARN:
 154                                 /* TODO: issue warning when warning API is available */;
 155                                 break;
 156                         default:
 157                                 break;
 158                         }
 159                 }
 160
 161                 /*
 162                  * We're currently not going to even try to convert stuff
 163                  * that has bare CR characters. Does anybody do that crazy
 164                  * stuff?
 165                  */
 166                 if (stats.cr != stats.crlf)
 167                         return GIT_PASSTHROUGH;
 168
 169                 if (ca->crlf_action == GIT_CRLF_GUESS) {
 170                         /*
 171                          * If the file in the index has any CR in it, do not convert.
 172                          * This is the new safer autocrlf handling.
 173                          */
 174                         if (has_cr_in_index(src))
 175                                 return GIT_PASSTHROUGH;
 176                 }
 177
 178                 if (!stats.cr)
 179                         return GIT_PASSTHROUGH;
 180         }
 181
 182         /* Actually drop the carriage returns */
 183         return git_buf_text_crlf_to_lf(to, from);
 184 }
 185
 186 static const char *line_ending(struct crlf_attrs *ca)
 187 {
 188         switch (ca->crlf_action) {
 189         case GIT_CRLF_BINARY:
 190         case GIT_CRLF_INPUT:
 191                 return "\n";
 192
 193         case GIT_CRLF_CRLF:
 194                 return "\r\n";
 195
 196         case GIT_CRLF_GUESS:
 197                 if (ca->auto_crlf == GIT_AUTO_CRLF_FALSE)
 198                         return "\n";
 199                 break;
 200
 201         case GIT_CRLF_AUTO:
 202         case GIT_CRLF_TEXT:
 203                 break;
 204
 205         default:
 206                 goto line_ending_error;
 207         }
 208
 209         if (ca->auto_crlf == GIT_AUTO_CRLF_TRUE)
 210                 return "\r\n";
 211         else if (ca->auto_crlf == GIT_AUTO_CRLF_INPUT)
 212                 return "\n";
 213         else if (ca->eol == GIT_EOL_UNSET)
 214                 return GIT_EOL_NATIVE == GIT_EOL_CRLF ? "\r\n" : "\n";
 215         else if (ca->eol == GIT_EOL_LF)
 216                 return "\n";
 217         else if (ca->eol == GIT_EOL_CRLF)
 218                 return "\r\n";
 219
 220 line_ending_error:
 221         giterr_set(GITERR_INVALID, "invalid input to line ending filter");
 222         return NULL;
 223 }
 224
 225 static int crlf_apply_to_workdir(
 226         struct crlf_attrs *ca, git_buf *to, const git_buf *from)
 227 {
 228         git_buf_text_stats stats;
 229         const char *workdir_ending = NULL;
 230         bool is_binary;
 231
 232         /* Empty file? Nothing to do. */
 233         if (git_buf_len(from) == 0)
 234                 return 0;
 235
 236         /* Determine proper line ending */
 237         workdir_ending = line_ending(ca);
 238         if (!workdir_ending)
 239                 return -1;
 240
 241         /* only LF->CRLF conversion is supported, do nothing on LF platforms */
 242         if (strcmp(workdir_ending, "\r\n") != 0)
 243                 return GIT_PASSTHROUGH;
 244
 245         /* If there are no LFs, or all LFs are part of a CRLF, nothing to do */
 246         is_binary = git_buf_text_gather_stats(&stats, from, false);
 247
 248         if (stats.lf == 0 || stats.lf == stats.crlf)
 249                 return GIT_PASSTHROUGH;
 250
 251         if (ca->crlf_action == GIT_CRLF_AUTO ||
 252                 ca->crlf_action == GIT_CRLF_GUESS) {
 253
 254                 /* If we have any existing CR or CRLF line endings, do nothing */
 255                 if (ca->crlf_action == GIT_CRLF_GUESS &&
 256                         stats.cr > 0 && stats.crlf > 0)
 257                         return GIT_PASSTHROUGH;
 258
 259                 /* If we have bare CR characters, do nothing */
 260                 if (stats.cr != stats.crlf)
 261                         return GIT_PASSTHROUGH;
 262
 263                 /* Don't filter binary files */
 264                 if (is_binary)
 265                         return GIT_PASSTHROUGH;
 266         }
 267
 268         return git_buf_text_lf_to_crlf(to, from);
 269 }
 270
 271 static int crlf_check(
 272         git_filter        *self,
 273         void              **payload, /* points to NULL ptr on entry, may be set */
 274         const git_filter_source *src,
 275         const char **attr_values)
 276 {
 277         int error;
 278         struct crlf_attrs ca;
 279
 280         GIT_UNUSED(self);
 281
 282         if (!attr_values) {
 283                 ca.crlf_action = GIT_CRLF_GUESS;
 284                 ca.eol = GIT_EOL_UNSET;
 285         } else {
 286                 ca.crlf_action = check_crlf(attr_values[2]); /* text */
 287                 if (ca.crlf_action == GIT_CRLF_GUESS)
 288                         ca.crlf_action = check_crlf(attr_values[0]); /* clrf */
 289                 ca.eol = check_eol(attr_values[1]); /* eol */
 290         }
 291         ca.auto_crlf = GIT_AUTO_CRLF_DEFAULT;
 292         ca.safe_crlf = GIT_SAFE_CRLF_DEFAULT;
 293
 294         /*
 295          * Use the core Git logic to see if we should perform CRLF for this file
 296          * based on its attributes & the value of `core.autocrlf`
 297          */
 298         ca.crlf_action = crlf_input_action(&ca);
 299
 300         if (ca.crlf_action == GIT_CRLF_BINARY)
 301                 return GIT_PASSTHROUGH;
 302
 303         if (ca.crlf_action == GIT_CRLF_GUESS ||
 304                 ((ca.crlf_action == GIT_CRLF_AUTO || ca.crlf_action == GIT_CRLF_TEXT) &&
 305                 git_filter_source_mode(src) == GIT_FILTER_SMUDGE)) {
 306
 307                 error = git_repository__cvar(
 308                         &ca.auto_crlf, git_filter_source_repo(src), GIT_CVAR_AUTO_CRLF);
 309                 if (error < 0)
 310                         return error;
 311
 312                 if (ca.crlf_action == GIT_CRLF_GUESS &&
 313                         ca.auto_crlf == GIT_AUTO_CRLF_FALSE)
 314                         return GIT_PASSTHROUGH;
 315
 316                 if (ca.auto_crlf == GIT_AUTO_CRLF_INPUT &&
 317                         git_filter_source_mode(src) == GIT_FILTER_SMUDGE)
 318                         return GIT_PASSTHROUGH;
 319         }
 320
 321         if (git_filter_source_mode(src) == GIT_FILTER_CLEAN) {
 322                 error = git_repository__cvar(
 323                         &ca.safe_crlf, git_filter_source_repo(src), GIT_CVAR_SAFE_CRLF);
 324                 if (error < 0)
 325                         return error;
 326
 327                 /* downgrade FAIL to WARN if ALLOW_UNSAFE option is used */
 328                 if ((git_filter_source_flags(src) & GIT_FILTER_ALLOW_UNSAFE) &&
 329                         ca.safe_crlf == GIT_SAFE_CRLF_FAIL)
 330                         ca.safe_crlf = GIT_SAFE_CRLF_WARN;
 331         }
 332
 333         *payload = git__malloc(sizeof(ca));
 334         GITERR_CHECK_ALLOC(*payload);
 335         memcpy(*payload, &ca, sizeof(ca));
 336
 337         return 0;
 338 }
 339
 340 static int crlf_apply(
 341         git_filter    *self,
 342         void         **payload, /* may be read and/or set */
 343         git_buf       *to,
 344         const git_buf *from,
 345         const git_filter_source *src)
 346 {
 347         /* initialize payload in case `check` was bypassed */
 348         if (!*payload) {
 349                 int error = crlf_check(self, payload, src, NULL);
 350                 if (error < 0)
 351                         return error;
 352         }
 353
 354         if (git_filter_source_mode(src) == GIT_FILTER_SMUDGE)
 355                 return crlf_apply_to_workdir(*payload, to, from);
 356         else
 357                 return crlf_apply_to_odb(*payload, to, from, src);
 358 }
 359
 360 static void crlf_cleanup(
 361         git_filter *self,
 362         void       *payload)
 363 {
 364         GIT_UNUSED(self);
 365         git__free(payload);
 366 }
 367
 368 git_filter *git_crlf_filter_new(void)
 369 {
 370         struct crlf_filter *f = git__calloc(1, sizeof(struct crlf_filter));
 371         if (f == NULL)
 372                 return NULL;
 373
 374         f->f.version = GIT_FILTER_VERSION;
 375         f->f.attributes = "crlf eol text";
 376         f->f.initialize = NULL;
 377         f->f.shutdown = git_filter_free;
 378         f->f.check    = crlf_check;
 379         f->f.apply    = crlf_apply;
 380         f->f.cleanup  = crlf_cleanup;
 381
 382         return (git_filter *)f;
 383 }