YT-19324: move YT provider to ydb/library/yql

This commit is formed by the following script: https://paste.yandex-team.ru/6f92e4b8-efc5-4d34-948b-15ee2accd7e7/text.
This commit has zero effect on all projects that depend on YQL.

The summary of changes:
- `yql/providers/yt -> ydb/library/yql/providers/yt `- the whole implementation of YT provider is moved into YDB code base for further export as a part of YT YQL plugin shared library;
- `yql/providers/stat/{expr_nodes,uploader} -> ydb/library/yql/providers/stat/{expr_nodes,uploader}` - a small interface without implementation and the description of stat expr nodes;
- `yql/core/extract_predicate/ut -> ydb/library/yql/core/extract_predicate/ut`;
- `yql/core/{ut,ut_common} -> ydb/library/yql/core/{ut,ut_common}`;
- `yql/core` is gone;
- `yql/library/url_preprocessing -> ydb/library/yql/core/url_preprocessing`.

**NB**: all new targets inside `ydb/` are under `IF (NOT CMAKE_EXPORT)` clause which disables them from open-source cmake generation and ya make build. They will be enabled in the subsequent commits.

1 files changed, 104 insertions, 0 deletions

diff --git a/contrib/libs/backtrace/posix.c b/contrib/libs/backtrace/posix.c
new file mode 100644
index 0000000000..924631d2e6
--- /dev/null
+++ b/contrib/libs/backtrace/posix.c
@@ -0,0 +1,104 @@
+/* posix.c -- POSIX file I/O routines for the backtrace library.
+   Copyright (C) 2012-2021 Free Software Foundation, Inc.
+   Written by Ian Lance Taylor, Google.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+    (1) Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+
+    (2) Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in
+    the documentation and/or other materials provided with the
+    distribution.
+
+    (3) The name of the author may not be used to
+    endorse or promote products derived from this software without
+    specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.  */
+
+#include "config.h"
+
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "backtrace.h"
+#include "internal.h"
+
+#ifndef O_BINARY
+#define O_BINARY 0
+#endif
+
+#ifndef O_CLOEXEC
+#define O_CLOEXEC 0
+#endif
+
+#ifndef FD_CLOEXEC
+#define FD_CLOEXEC 1
+#endif
+
+/* Open a file for reading.  */
+
+int
+backtrace_open (const char *filename, backtrace_error_callback error_callback,
+		void *data, int *does_not_exist)
+{
+  int descriptor;
+
+  if (does_not_exist != NULL)
+    *does_not_exist = 0;
+
+  descriptor = open (filename, (int) (O_RDONLY | O_BINARY | O_CLOEXEC));
+  if (descriptor < 0)
+    {
+      /* If DOES_NOT_EXIST is not NULL, then don't call ERROR_CALLBACK
+	 if the file does not exist.  We treat lacking permission to
+	 open the file as the file not existing; this case arises when
+	 running the libgo syscall package tests as root.  */
+      if (does_not_exist != NULL && (errno == ENOENT || errno == EACCES))
+	*does_not_exist = 1;
+      else
+	error_callback (data, filename, errno);
+      return -1;
+    }
+
+#ifdef HAVE_FCNTL
+  /* Set FD_CLOEXEC just in case the kernel does not support
+     O_CLOEXEC. It doesn't matter if this fails for some reason.
+     FIXME: At some point it should be safe to only do this if
+     O_CLOEXEC == 0.  */
+  fcntl (descriptor, F_SETFD, FD_CLOEXEC);
+#endif
+
+  return descriptor;
+}
+
+/* Close DESCRIPTOR.  */
+
+int
+backtrace_close (int descriptor, backtrace_error_callback error_callback,
+		 void *data)
+{
+  if (close (descriptor) < 0)
+    {
+      error_callback (data, "close", errno);
+      return 0;
+    }
+  return 1;
+}