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dir-iterator: add flags parameter to dir_iterator_begin

Add the possibility of giving flags to dir_iterator_begin to initialize
a dir-iterator with special options.

Currently possible flags are:
- DIR_ITERATOR_PEDANTIC, which makes dir_iterator_advance abort
immediately in the case of an error, instead of keep looking for the
next valid entry;
- DIR_ITERATOR_FOLLOW_SYMLINKS, which makes the iterator follow
symlinks and include linked directories' contents in the iteration.

These new flags will be used in a subsequent patch.

Also add tests for the flags' usage and adjust refs/files-backend.c to
the new dir_iterator_begin signature.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
tags/v2.23.0-rc0
Matheus Tavares Junio C Hamano 3 months ago
parent
commit
fa1da7d2ee
5 changed files with 191 additions and 36 deletions
  1. +39
    -17
      dir-iterator.c
  2. +44
    -11
      dir-iterator.h
  3. +1
    -1
      refs/files-backend.c
  4. +27
    -7
      t/helper/test-dir-iterator.c
  5. +80
    -0
      t/t0066-dir-iterator.sh

+ 39
- 17
dir-iterator.c View File

@@ -38,13 +38,16 @@ struct dir_iterator_int {
* that will be included in this iteration.
*/
struct dir_iterator_level *levels;

/* Combination of flags for this dir-iterator */
unsigned int flags;
};

/*
* Push a level in the iter stack and initialize it with information from
* the directory pointed by iter->base->path. It is assumed that this
* strbuf points to a valid directory path. Return 0 on success and -1
* otherwise, leaving the stack unchanged.
* otherwise, setting errno accordingly and leaving the stack unchanged.
*/
static int push_level(struct dir_iterator_int *iter)
{
@@ -59,11 +62,13 @@ static int push_level(struct dir_iterator_int *iter)

level->dir = opendir(iter->base.path.buf);
if (!level->dir) {
int saved_errno = errno;
if (errno != ENOENT) {
warning_errno("error opening directory '%s'",
iter->base.path.buf);
}
iter->levels_nr--;
errno = saved_errno;
return -1;
}

@@ -90,11 +95,13 @@ static int pop_level(struct dir_iterator_int *iter)
/*
* Populate iter->base with the necessary information on the next iteration
* entry, represented by the given dirent de. Return 0 on success and -1
* otherwise.
* otherwise, setting errno accordingly.
*/
static int prepare_next_entry_data(struct dir_iterator_int *iter,
struct dirent *de)
{
int err, saved_errno;

strbuf_addstr(&iter->base.path, de->d_name);
/*
* We have to reset these because the path strbuf might have
@@ -105,13 +112,17 @@ static int prepare_next_entry_data(struct dir_iterator_int *iter,
iter->base.basename = iter->base.path.buf +
iter->levels[iter->levels_nr - 1].prefix_len;

if (lstat(iter->base.path.buf, &iter->base.st)) {
if (errno != ENOENT)
warning_errno("failed to stat '%s'", iter->base.path.buf);
return -1;
}
if (iter->flags & DIR_ITERATOR_FOLLOW_SYMLINKS)
err = stat(iter->base.path.buf, &iter->base.st);
else
err = lstat(iter->base.path.buf, &iter->base.st);

return 0;
saved_errno = errno;
if (err && errno != ENOENT)
warning_errno("failed to stat '%s'", iter->base.path.buf);

errno = saved_errno;
return err;
}

int dir_iterator_advance(struct dir_iterator *dir_iterator)
@@ -119,11 +130,11 @@ int dir_iterator_advance(struct dir_iterator *dir_iterator)
struct dir_iterator_int *iter =
(struct dir_iterator_int *)dir_iterator;

if (S_ISDIR(iter->base.st.st_mode)) {
if (push_level(iter) && iter->levels_nr == 0) {
/* Pushing the first level failed */
return dir_iterator_abort(dir_iterator);
}
if (S_ISDIR(iter->base.st.st_mode) && push_level(iter)) {
if (errno != ENOENT && iter->flags & DIR_ITERATOR_PEDANTIC)
goto error_out;
if (iter->levels_nr == 0)
goto error_out;
}

/* Loop until we find an entry that we can give back to the caller. */
@@ -137,22 +148,32 @@ int dir_iterator_advance(struct dir_iterator *dir_iterator)
de = readdir(level->dir);

if (!de) {
if (errno)
if (errno) {
warning_errno("error reading directory '%s'",
iter->base.path.buf);
else if (pop_level(iter) == 0)
if (iter->flags & DIR_ITERATOR_PEDANTIC)
goto error_out;
} else if (pop_level(iter) == 0) {
return dir_iterator_abort(dir_iterator);
}
continue;
}

if (is_dot_or_dotdot(de->d_name))
continue;

if (prepare_next_entry_data(iter, de))
if (prepare_next_entry_data(iter, de)) {
if (errno != ENOENT && iter->flags & DIR_ITERATOR_PEDANTIC)
goto error_out;
continue;
}

return ITER_OK;
}

error_out:
dir_iterator_abort(dir_iterator);
return ITER_ERROR;
}

int dir_iterator_abort(struct dir_iterator *dir_iterator)
@@ -178,7 +199,7 @@ int dir_iterator_abort(struct dir_iterator *dir_iterator)
return ITER_DONE;
}

struct dir_iterator *dir_iterator_begin(const char *path)
struct dir_iterator *dir_iterator_begin(const char *path, unsigned int flags)
{
struct dir_iterator_int *iter = xcalloc(1, sizeof(*iter));
struct dir_iterator *dir_iterator = &iter->base;
@@ -189,6 +210,7 @@ struct dir_iterator *dir_iterator_begin(const char *path)

ALLOC_GROW(iter->levels, 10, iter->levels_alloc);
iter->levels_nr = 0;
iter->flags = flags;

/*
* Note: stat already checks for NULL or empty strings and

+ 44
- 11
dir-iterator.h View File

@@ -20,7 +20,8 @@
* A typical iteration looks like this:
*
* int ok;
* struct dir_iterator *iter = dir_iterator_begin(path);
* unsigned int flags = DIR_ITERATOR_PEDANTIC;
* struct dir_iterator *iter = dir_iterator_begin(path, flags);
*
* if (!iter)
* goto error_handler;
@@ -44,6 +45,29 @@
* dir_iterator_advance() again.
*/

/*
* Flags for dir_iterator_begin:
*
* - DIR_ITERATOR_PEDANTIC: override dir-iterator's default behavior
* in case of an error at dir_iterator_advance(), which is to keep
* looking for a next valid entry. With this flag, resources are freed
* and ITER_ERROR is returned immediately. In both cases, a meaningful
* warning is emitted. Note: ENOENT errors are always ignored so that
* the API users may remove files during iteration.
*
* - DIR_ITERATOR_FOLLOW_SYMLINKS: make dir-iterator follow symlinks.
* i.e., linked directories' contents will be iterated over and
* iter->base.st will contain information on the referred files,
* not the symlinks themselves, which is the default behavior. Broken
* symlinks are ignored.
*
* Warning: circular symlinks are also followed when
* DIR_ITERATOR_FOLLOW_SYMLINKS is set. The iteration may end up with
* an ELOOP if they happen and DIR_ITERATOR_PEDANTIC is set.
*/
#define DIR_ITERATOR_PEDANTIC (1 << 0)
#define DIR_ITERATOR_FOLLOW_SYMLINKS (1 << 1)

struct dir_iterator {
/* The current path: */
struct strbuf path;
@@ -58,29 +82,38 @@ struct dir_iterator {
/* The current basename: */
const char *basename;

/* The result of calling lstat() on path: */
/*
* The result of calling lstat() on path; or stat(), if the
* DIR_ITERATOR_FOLLOW_SYMLINKS flag was set at
* dir_iterator's initialization.
*/
struct stat st;
};

/*
* Start a directory iteration over path. On success, return a
* dir_iterator that holds the internal state of the iteration.
* In case of failure, return NULL and set errno accordingly.
* Start a directory iteration over path with the combination of
* options specified by flags. On success, return a dir_iterator
* that holds the internal state of the iteration. In case of
* failure, return NULL and set errno accordingly.
*
* The iteration includes all paths under path, not including path
* itself and not including "." or ".." entries.
*
* path is the starting directory. An internal copy will be made.
* Parameters are:
* - path is the starting directory. An internal copy will be made.
* - flags is a combination of the possible flags to initialize a
* dir-iterator or 0 for default behavior.
*/
struct dir_iterator *dir_iterator_begin(const char *path);
struct dir_iterator *dir_iterator_begin(const char *path, unsigned int flags);

/*
* Advance the iterator to the first or next item and return ITER_OK.
* If the iteration is exhausted, free the dir_iterator and any
* resources associated with it and return ITER_DONE. On error, free
* dir_iterator and associated resources and return ITER_ERROR. It is
* a bug to use iterator or call this function again after it has
* returned ITER_DONE or ITER_ERROR.
* resources associated with it and return ITER_DONE.
*
* It is a bug to use iterator or call this function again after it
* has returned ITER_DONE or ITER_ERROR (which may be returned iff
* the DIR_ITERATOR_PEDANTIC flag was set).
*/
int dir_iterator_advance(struct dir_iterator *iterator);


+ 1
- 1
refs/files-backend.c View File

@@ -2150,7 +2150,7 @@ static struct ref_iterator *reflog_iterator_begin(struct ref_store *ref_store,

strbuf_addf(&sb, "%s/logs", gitdir);

diter = dir_iterator_begin(sb.buf);
diter = dir_iterator_begin(sb.buf, 0);
if(!diter)
return empty_ref_iterator_begin();


+ 27
- 7
t/helper/test-dir-iterator.c View File

@@ -4,29 +4,44 @@
#include "iterator.h"
#include "dir-iterator.h"

/* Argument is a directory path to iterate over */
/*
* usage:
* tool-test dir-iterator [--follow-symlinks] [--pedantic] directory_path
*/
int cmd__dir_iterator(int argc, const char **argv)
{
struct strbuf path = STRBUF_INIT;
struct dir_iterator *diter;
unsigned int flags = 0;
int iter_status;

for (++argv, --argc; *argv && starts_with(*argv, "--"); ++argv, --argc) {
if (strcmp(*argv, "--follow-symlinks") == 0)
flags |= DIR_ITERATOR_FOLLOW_SYMLINKS;
else if (strcmp(*argv, "--pedantic") == 0)
flags |= DIR_ITERATOR_PEDANTIC;
else
die("invalid option '%s'", *argv);
}

if (argc < 2)
die("BUG: test-dir-iterator needs one argument");

strbuf_add(&path, argv[1], strlen(argv[1]));
if (!*argv || argc != 1)
die("dir-iterator needs exactly one non-option argument");

diter = dir_iterator_begin(path.buf);
strbuf_add(&path, *argv, strlen(*argv));
diter = dir_iterator_begin(path.buf, flags);

if (!diter) {
printf("dir_iterator_begin failure: %d\n", errno);
exit(EXIT_FAILURE);
}

while (dir_iterator_advance(diter) == ITER_OK) {
while ((iter_status = dir_iterator_advance(diter)) == ITER_OK) {
if (S_ISDIR(diter->st.st_mode))
printf("[d] ");
else if (S_ISREG(diter->st.st_mode))
printf("[f] ");
else if (S_ISLNK(diter->st.st_mode))
printf("[s] ");
else
printf("[?] ");

@@ -34,5 +49,10 @@ int cmd__dir_iterator(int argc, const char **argv)
diter->path.buf);
}

if (iter_status != ITER_DONE) {
printf("dir_iterator_advance failure\n");
return 1;
}

return 0;
}

+ 80
- 0
t/t0066-dir-iterator.sh View File

@@ -65,4 +65,84 @@ test_expect_success 'begin should fail upon non directory paths' '
test_cmp expected-non-dir-output actual-non-dir-output
'

test_expect_success POSIXPERM,SANITY 'advance should not fail on errors by default' '
cat >expected-no-permissions-output <<-EOF &&
[d] (a) [a] ./dir3/a
EOF

mkdir -p dir3/a &&
>dir3/a/b &&
chmod 0 dir3/a &&

test-tool dir-iterator ./dir3 >actual-no-permissions-output &&
test_cmp expected-no-permissions-output actual-no-permissions-output &&
chmod 755 dir3/a &&
rm -rf dir3
'

test_expect_success POSIXPERM,SANITY 'advance should fail on errors, w/ pedantic flag' '
cat >expected-no-permissions-pedantic-output <<-EOF &&
[d] (a) [a] ./dir3/a
dir_iterator_advance failure
EOF

mkdir -p dir3/a &&
>dir3/a/b &&
chmod 0 dir3/a &&

test_must_fail test-tool dir-iterator --pedantic ./dir3 \
>actual-no-permissions-pedantic-output &&
test_cmp expected-no-permissions-pedantic-output \
actual-no-permissions-pedantic-output &&
chmod 755 dir3/a &&
rm -rf dir3
'

test_expect_success SYMLINKS 'setup dirs with symlinks' '
mkdir -p dir4/a &&
mkdir -p dir4/b/c &&
>dir4/a/d &&
ln -s d dir4/a/e &&
ln -s ../b dir4/a/f &&

mkdir -p dir5/a/b &&
mkdir -p dir5/a/c &&
ln -s ../c dir5/a/b/d &&
ln -s ../ dir5/a/b/e &&
ln -s ../../ dir5/a/b/f
'

test_expect_success SYMLINKS 'dir-iterator should not follow symlinks by default' '
cat >expected-no-follow-sorted-output <<-EOF &&
[d] (a) [a] ./dir4/a
[d] (b) [b] ./dir4/b
[d] (b/c) [c] ./dir4/b/c
[f] (a/d) [d] ./dir4/a/d
[s] (a/e) [e] ./dir4/a/e
[s] (a/f) [f] ./dir4/a/f
EOF

test-tool dir-iterator ./dir4 >out &&
sort out >actual-no-follow-sorted-output &&

test_cmp expected-no-follow-sorted-output actual-no-follow-sorted-output
'

test_expect_success SYMLINKS 'dir-iterator should follow symlinks w/ follow flag' '
cat >expected-follow-sorted-output <<-EOF &&
[d] (a) [a] ./dir4/a
[d] (a/f) [f] ./dir4/a/f
[d] (a/f/c) [c] ./dir4/a/f/c
[d] (b) [b] ./dir4/b
[d] (b/c) [c] ./dir4/b/c
[f] (a/d) [d] ./dir4/a/d
[f] (a/e) [e] ./dir4/a/e
EOF

test-tool dir-iterator --follow-symlinks ./dir4 >out &&
sort out >actual-follow-sorted-output &&

test_cmp expected-follow-sorted-output actual-follow-sorted-output
'

test_done

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