Merge branch 'hn/reftable'

The "reftable" backend for the refs API, without integrating into
the refs subsystem, has been added.

* hn/reftable:
  Add "test-tool dump-reftable" command.
  reftable: add dump utility
  reftable: implement stack, a mutable database of reftable files.
  reftable: implement refname validation
  reftable: add merged table view
  reftable: add a heap-based priority queue for reftable records
  reftable: reftable file level tests
  reftable: read reftable files
  reftable: generic interface to tables
  reftable: write reftable files
  reftable: a generic binary tree implementation
  reftable: reading/writing blocks
  Provide zlib's uncompress2 from compat/zlib-compat.c
  reftable: (de)serialization for the polymorphic record type.
  reftable: add blocksource, an abstraction for random access reads
  reftable: utility functions
  reftable: add error related functionality
  reftable: add LICENSE
  hash.h: provide constants for the hash IDs

1 files changed, 62 insertions, 0 deletions

diff --git a/reftable/reftable-error.h b/reftable/reftable-error.h
new file mode 100644
index 0000000000..6f89bedf1a
--- /dev/null
+++ b/reftable/reftable-error.h
@@ -0,0 +1,62 @@
+/*
+Copyright 2020 Google LLC
+
+Use of this source code is governed by a BSD-style
+license that can be found in the LICENSE file or at
+https://developers.google.com/open-source/licenses/bsd
+*/
+
+#ifndef REFTABLE_ERROR_H
+#define REFTABLE_ERROR_H
+
+/*
+ * Errors in reftable calls are signaled with negative integer return values. 0
+ * means success.
+ */
+enum reftable_error {
+	/* Unexpected file system behavior */
+	REFTABLE_IO_ERROR = -2,
+
+	/* Format inconsistency on reading data */
+	REFTABLE_FORMAT_ERROR = -3,
+
+	/* File does not exist. Returned from block_source_from_file(), because
+	 * it needs special handling in stack.
+	 */
+	REFTABLE_NOT_EXIST_ERROR = -4,
+
+	/* Trying to write out-of-date data. */
+	REFTABLE_LOCK_ERROR = -5,
+
+	/* Misuse of the API:
+	 *  - on writing a record with NULL refname.
+	 *  - on writing a reftable_ref_record outside the table limits
+	 *  - on writing a ref or log record before the stack's
+	 * next_update_inde*x
+	 *  - on writing a log record with multiline message with
+	 *  exact_log_message unset
+	 *  - on reading a reftable_ref_record from log iterator, or vice versa.
+	 *
+	 * When a call misuses the API, the internal state of the library is
+	 * kept unchanged.
+	 */
+	REFTABLE_API_ERROR = -6,
+
+	/* Decompression error */
+	REFTABLE_ZLIB_ERROR = -7,
+
+	/* Wrote a table without blocks. */
+	REFTABLE_EMPTY_TABLE_ERROR = -8,
+
+	/* Dir/file conflict. */
+	REFTABLE_NAME_CONFLICT = -9,
+
+	/* Invalid ref name. */
+	REFTABLE_REFNAME_ERROR = -10,
+};
+
+/* convert the numeric error code to a string. The string should not be
+ * deallocated. */
+const char *reftable_error_str(int err);
+
+#endif