On Mon, 2011-02-28, I (Julian Foad) wrote:
> On Sat, 2011-02-26, Branko Čibej wrote:
> > On 26.02.2011 20:40, Ivan Zhakov wrote:
> > > Btw I think it makes sense rename file to tmp directory in working
> > > copy instead of pristines directory, since it could be crash/failure
> > > between rename and delete. In this case pristines directory will
> > > polluted with orphaned pristines.
> >
> > That works as long as the pristine store lives in the WC root, so yes.
>
> This seems to be a good plan. Thanks for the help. I'll do it right
> away.
Please see attached patch. (I might write a test or two before
committing it or I might commit first.)
- Julian
Update the pristine text store to guarantee that a pristine text stream
being read will remain readable even if the text is deleted from the store.
### The '#ifdef WIN32' is here shown replaced with '#if 1' so it can be tested on Linux.
* subversion/libsvn_wc/wc_db.h
(svn_wc__db_pristine_read): State that the stream will remain readable.
Also document 'db' and 'wri_abspath'.
* subversion/libsvn_wc/wc_db_pristine.c
(pristine_read_txn): Document that the stream will remain readable.
(pristine_get_tempdir): New function, factored out of ...
(svn_wc__db_pristine_get_tempdir): ... here.
(remove_file): New function.
(pristine_remove_baton_t): Add a 'wcroot' object.
(pristine_remove_if_unreferenced_txn): Use remove_file() so that file
removal can always be followed by re-creating a new file of the same
name even on Windows.
(pristine_remove_if_unreferenced): Initialize the new member of the
pristine_remove_baton_t.
--This line, and those below, will be ignored--
Index: subversion/libsvn_wc/wc_db.h
===================================================================
--- subversion/libsvn_wc/wc_db.h (revision 1075304)
+++ subversion/libsvn_wc/wc_db.h (working copy)
@@ -890,7 +890,11 @@ svn_wc__db_pristine_get_future_path(cons
/* Set *CONTENTS to a readable stream that will yield the pristine text
- identified by CHECKSUM (### which should/must be its SHA-1 checksum?).
+ identified by SHA1_CHECKSUM (### which should/must be its SHA-1 checksum?)
+ within the WC identified by WRI_ABSPATH in DB.
+
+ Even if the pristine text is removed from the store while it is being
+ read, the stream will remain valid and readable until it is closed.
Allocate the stream in RESULT_POOL. */
svn_error_t *
Index: subversion/libsvn_wc/wc_db_pristine.c
===================================================================
--- subversion/libsvn_wc/wc_db_pristine.c (revision 1075328)
+++ subversion/libsvn_wc/wc_db_pristine.c (working copy)
@@ -182,6 +182,9 @@ typedef struct pristine_read_baton_t
* identified by BATON->sha1_checksum can be read from the pristine store of
* SDB. If that text is not in the pristine store, return an error.
*
+ * Even if the pristine text is removed from the store while it is being
+ * read, the stream will remain valid and readable until it is closed.
+ *
* Allocate the stream in BATON->result_pool.
*
* This function expects to be executed inside a SQLite txn.
@@ -211,6 +214,8 @@ pristine_read_txn(void *baton,
b->sha1_checksum, scratch_pool));
}
+ /* Open the file as a readable stream. It will remain readable even when
+ * deleted from disk; APR guarantees that on Windows as well as Unix. */
SVN_ERR(svn_stream_open_readonly(b->contents, b->pristine_abspath,
b->result_pool, scratch_pool));
return SVN_NO_ERROR;
@@ -258,6 +263,18 @@ svn_wc__db_pristine_read(svn_stream_t **
}
+/* Return the absolute path to the temporary directory for pristine text
+ files within WCROOT. */
+static char *
+pristine_get_tempdir(svn_wc__db_wcroot_t *wcroot,
+ apr_pool_t *result_pool,
+ apr_pool_t *scratch_pool)
+{
+ return svn_dirent_join_many(result_pool, wcroot->abspath,
+ svn_wc_get_adm_dir(scratch_pool),
+ PRISTINE_TEMPDIR_RELPATH, (char *)NULL);
+}
+
svn_error_t *
svn_wc__db_pristine_get_tempdir(const char **temp_dir_abspath,
svn_wc__db_t *db,
@@ -276,10 +293,7 @@ svn_wc__db_pristine_get_tempdir(const ch
scratch_pool, scratch_pool));
VERIFY_USABLE_WCROOT(wcroot);
- *temp_dir_abspath = svn_dirent_join_many(result_pool, wcroot->abspath,
- svn_wc_get_adm_dir(scratch_pool),
- PRISTINE_TEMPDIR_RELPATH,
- NULL);
+ *temp_dir_abspath = pristine_get_tempdir(wcroot, result_pool, scratch_pool);
return SVN_NO_ERROR;
}
@@ -499,9 +513,48 @@ svn_wc__db_pristine_get_sha1(const svn_c
}
+/* Remove the file at FILE_ABSPATH in such a way that we could re-create a
+ * new file of the same name at any time thereafter.
+ *
+ * On Windows, the file will not disappear immediately from the directory if
+ * it is still being read so the best thing to do is first rename it to a
+ * unique name. */
+static svn_error_t *
+remove_file(const char *file_abspath,
+ svn_wc__db_wcroot_t *wcroot,
+ svn_boolean_t ignore_enoent,
+ apr_pool_t *scratch_pool)
+{
+#if 1 /* ### #ifdef WIN32 */
+ {
+ svn_error_t *err;
+ const char *temp_abspath;
+ const char *temp_dir_abspath
+ = pristine_get_tempdir(wcroot, scratch_pool, scratch_pool);
+
+ /* To rename the file to a unique name in the temp dir, first create a
+ * uniquely named file in the temp dir and then overwrite it. */
+ SVN_ERR(svn_io_open_unique_file3(NULL, &temp_abspath, temp_dir_abspath,
+ svn_io_file_del_none,
+ scratch_pool, scratch_pool));
+ err = svn_io_file_rename(file_abspath, temp_abspath, scratch_pool);
+ if (err && ignore_enoent && APR_STATUS_IS_ENOENT(err->apr_err))
+ svn_error_clear(err);
+ else
+ SVN_ERR(err);
+ file_abspath = temp_abspath;
+ }
+#endif
+
+ SVN_ERR(svn_io_remove_file2(file_abspath, ignore_enoent, scratch_pool));
+
+ return SVN_NO_ERROR;
+}
+
/* Data for pristine_remove_if_unreferenced_txn(). */
typedef struct pristine_remove_baton_t
{
+ svn_wc__db_wcroot_t *wcroot;
/* The pristine text's SHA-1 checksum. */
const svn_checksum_t *sha1_checksum;
/* The path to the pristine file (within the pristine store). */
@@ -542,8 +595,8 @@ pristine_remove_if_unreferenced_txn(void
svn_boolean_t ignore_enoent = TRUE;
#endif
- SVN_ERR(svn_io_remove_file2(b->pristine_abspath, ignore_enoent,
- scratch_pool));
+ SVN_ERR(remove_file(b->pristine_abspath, b->wcroot, ignore_enoent,
+ scratch_pool));
}
return SVN_NO_ERROR;
@@ -561,6 +614,7 @@ pristine_remove_if_unreferenced(svn_wc__
{
pristine_remove_baton_t b;
+ b.wcroot = wcroot;
b.sha1_checksum = sha1_checksum;
SVN_ERR(get_pristine_fname(&b.pristine_abspath, wcroot->abspath,
sha1_checksum, FALSE /* create_subdir */,
