[Tarantool-patches] [PATCH 2.X v3] module api: box_ibuf_* wrappers

[Timur Safin <tsafin@tarantool.org>]

Introduced the bare minimum of ibuf accessors, which make
external merger possible:
- box_ibuf_reserve
- box_ibuf_read_range
- box_ibuf_write_range

Part of #5384
---

 Vlad, Sasha, I'm sending this patch as a follow-up to v3 of patchset, to make
 possible early review, before other patches in patchset have been
 finally polished.

 This pretty much compatible to that we discussed early on in Zoom (though...
 some extra, awkward level of indirection was introduced, but I had to)


 src/CMakeLists.txt               |  1 +
 src/box/CMakeLists.txt           |  1 +
 src/box/box_ibuf.c               | 62 +++++++++++++++++++++++++++++
 src/box/box_ibuf.h               | 68 ++++++++++++++++++++++++++++++++
 src/exports.h                    |  3 ++
 test/app-tap/module_api.c        | 34 ++++++++++++++++
 test/app-tap/module_api.test.lua |  2 +-
 7 files changed, 170 insertions(+), 1 deletion(-)
 create mode 100644 src/box/box_ibuf.c
 create mode 100644 src/box/box_ibuf.h

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 699536652..0cff406e0 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -152,6 +152,7 @@ set(api_headers
     ${CMAKE_SOURCE_DIR}/src/box/tuple_extract_key.h
     ${CMAKE_SOURCE_DIR}/src/box/schema_def.h
     ${CMAKE_SOURCE_DIR}/src/box/box.h
+    ${CMAKE_SOURCE_DIR}/src/box/box_ibuf.h
     ${CMAKE_SOURCE_DIR}/src/box/index.h
     ${CMAKE_SOURCE_DIR}/src/box/iterator_type.h
     ${CMAKE_SOURCE_DIR}/src/box/error.h
diff --git a/src/box/CMakeLists.txt b/src/box/CMakeLists.txt
index 8b2e704cf..07d10dae8 100644
--- a/src/box/CMakeLists.txt
+++ b/src/box/CMakeLists.txt
@@ -191,6 +191,7 @@ add_library(box STATIC
     wal.c
     call.c
     merger.c
+    box_ibuf.c
     ${sql_sources}
     ${lua_sources}
     lua/init.c
diff --git a/src/box/box_ibuf.c b/src/box/box_ibuf.c
new file mode 100644
index 000000000..5cf3ab711
--- /dev/null
+++ b/src/box/box_ibuf.c
@@ -0,0 +1,62 @@
+/*
+ * Copyright 2020, Tarantool AUTHORS, please see AUTHORS file.
+ *
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY <COPYRIGHT HOLDER> ``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
+ * <COPYRIGHT HOLDER> OR CONTRIBUTORS 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 <stdlib.h>
+#include "box_ibuf.h"
+
+void *
+box_ibuf_reserve(box_ibuf_t *ibuf, size_t size)
+{
+	return ibuf_reserve(ibuf, size);
+}
+
+void
+box_ibuf_read_range(box_ibuf_t *ibuf, char ***rpos, char ***wpos)
+{
+	if (!ibuf)
+		return;
+	if (rpos)
+		*rpos = &ibuf->rpos;
+	if (wpos)
+		*wpos = &ibuf->wpos;
+}
+
+void
+box_ibuf_write_range(box_ibuf_t *ibuf, char ***wpos, char ***end)
+{
+	if (!ibuf)
+		return;
+	if (wpos)
+		*wpos = &ibuf->wpos;
+	if (end)
+		*end = &ibuf->end;
+
+}
diff --git a/src/box/box_ibuf.h b/src/box/box_ibuf.h
new file mode 100644
index 000000000..235b87560
--- /dev/null
+++ b/src/box/box_ibuf.h
@@ -0,0 +1,68 @@
+#pragma once
+/*
+ * Copyright 2020, Tarantool AUTHORS, please see AUTHORS file.
+ *
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY <COPYRIGHT HOLDER> ``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
+ * <COPYRIGHT HOLDER> OR CONTRIBUTORS 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 <stddef.h>
+
+#include <trivia/util.h>
+#include <small/ibuf.h>
+
+#if defined(__cplusplus)
+extern "C" {
+#endif /* defined(__cplusplus) */
+
+/** \cond public */
+
+typedef struct ibuf box_ibuf_t;
+
+/**
+ * Reserve requested amount of bytes in ibuf buffer
+ */
+API_EXPORT void *
+box_ibuf_reserve(box_ibuf_t *ibuf, size_t size);
+
+/**
+ * Return pointers to read range pointers used [rpos..wpos)
+ */
+API_EXPORT void
+box_ibuf_read_range(box_ibuf_t *ibuf, char ***rpos, char ***wpos);
+
+/**
+ * Return pointers to write range pointers used [wpos..end)
+ */
+API_EXPORT void
+box_ibuf_write_range(box_ibuf_t *ibuf, char ***wpos, char ***end);
+
+/** \endcond public */
+
+#if defined(__cplusplus)
+} /* extern "C" */
+#endif /* defined(__cplusplus) */
diff --git a/src/exports.h b/src/exports.h
index 034b6c4a3..1342d34c4 100644
--- a/src/exports.h
+++ b/src/exports.h
@@ -17,6 +17,9 @@ EXPORT(box_error_last)
 EXPORT(box_error_message)
 EXPORT(box_error_set)
 EXPORT(box_error_type)
+EXPORT(box_ibuf_read_range)
+EXPORT(box_ibuf_reserve)
+EXPORT(box_ibuf_write_range)
 EXPORT(box_index_bsize)
 EXPORT(box_index_count)
 EXPORT(box_index_get)
diff --git a/test/app-tap/module_api.c b/test/app-tap/module_api.c
index 502d734d2..a681826bf 100644
--- a/test/app-tap/module_api.c
+++ b/test/app-tap/module_api.c
@@ -164,6 +164,39 @@ test_checkibuf(lua_State *L)
 	return 1;
 }
 
+static int
+test_box_ibuf(lua_State *L)
+{
+	(void)L;
+	struct slab_cache *slabc = cord_slab_cache();
+	assert(slabc != NULL);
+	box_ibuf_t ibuf;
+
+	ibuf_create(&ibuf, slabc, 16320);
+	assert(ibuf_used(&ibuf) == 0);
+	box_ibuf_reserve(&ibuf, 65536);
+	char **rpos;
+	char **wpos;
+	box_ibuf_read_range(&ibuf, &rpos, &wpos);
+
+	void *ptr = ibuf_alloc(&ibuf, 10);
+	assert(ptr != NULL);
+
+	assert(ibuf_used(&ibuf) == 10);
+	assert((*wpos - *rpos) == 10);
+
+	ptr = ibuf_alloc(&ibuf, 10000);
+	assert(ptr);
+	assert(ibuf_used(&ibuf) == 10010);
+	assert((*wpos - *rpos) == 10010);
+
+	ibuf_reset(&ibuf);
+	assert(ibuf_used(&ibuf) == 0);
+
+	lua_pushboolean(L, 1);
+	return 1;
+}
+
 static int
 test_touint64(lua_State *L)
 {
@@ -1216,6 +1249,7 @@ luaopen_module_api(lua_State *L)
 		{"test_key_def_dump_parts", test_key_def_dump_parts},
 		{"test_key_def_validate_tuple", test_key_def_validate_tuple},
 		{"tuple_validate", test_tuple_validate},
+		{"test_box_ibuf", test_box_ibuf},
 		{NULL, NULL}
 	};
 	luaL_register(L, "module_api", lib);
diff --git a/test/app-tap/module_api.test.lua b/test/app-tap/module_api.test.lua
index 17f4ff477..ff64bc36c 100755
--- a/test/app-tap/module_api.test.lua
+++ b/test/app-tap/module_api.test.lua
@@ -213,7 +213,7 @@ local function test_iscdata(test, module)
 end
 
 local test = require('tap').test("module_api", function(test)
-    test:plan(33)
+    test:plan(34)
     local status, module = pcall(require, 'module_api')
     test:is(status, true, "module")
     test:ok(status, "module is loaded")
-- 
2.20.1