[Tarantool-patches] [PATCH 2.X v4.1] 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
---

This is updated version for box_ibuf* wrappers, which accumulate fixes for
most of Sasha and Vlad comments, with exceptions of doxygen comments and 
some tests. Extra verbose comments with all dots put in will be sent 
in follow-up patchset to be sent quite soon, but not today.


Branches:
* https://github.com/tarantool/tarantool/tree/tsafin/gh-5273-expand-module-api-v4


 src/CMakeLists.txt               |  1 +
 src/box/CMakeLists.txt           |  1 +
 src/box/ibuf.c                   | 68 ++++++++++++++++++++++++++++
 src/box/ibuf.h                   | 76 ++++++++++++++++++++++++++++++++
 src/exports.h                    |  3 ++
 test/app-tap/module_api.c        | 44 ++++++++++++++++++
 test/app-tap/module_api.test.lua |  2 +-
 7 files changed, 194 insertions(+), 1 deletion(-)
 create mode 100644 src/box/ibuf.c
 create mode 100644 src/box/ibuf.h

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 699536652..3817f5c62 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/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..690de5e83 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
+    ibuf.c
     ${sql_sources}
     ${lua_sources}
     lua/init.c
diff --git a/src/box/ibuf.c b/src/box/ibuf.c
new file mode 100644
index 000000000..36ab2918d
--- /dev/null
+++ b/src/box/ibuf.c
@@ -0,0 +1,68 @@
+/*
+ * 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 "ibuf.h"
+#include "error.h"
+#include "diag.h"
+#include "small/ibuf.h"
+
+void *
+box_ibuf_reserve(box_ibuf_t *ibuf, size_t size)
+{
+	void * p = ibuf_reserve(ibuf, size);
+	if (p == NULL)
+		diag_set(OutOfMemory, size, "ibuf_reserve", "box_ibuf_reserve");
+
+	return p;
+}
+
+void
+box_ibuf_read_range(box_ibuf_t *ibuf, char ***rpos, char ***wpos)
+{
+	assert(ibuf != NULL);
+	if (rpos != NULL)
+		*rpos = &ibuf->rpos;
+	if (wpos != NULL)
+		*wpos = &ibuf->wpos;
+}
+
+void
+box_ibuf_write_range(box_ibuf_t *ibuf, char ***wpos, char ***end)
+{
+	assert(ibuf != NULL);
+	if (wpos != NULL)
+		*wpos = &ibuf->wpos;
+	if (end != NULL)
+		*end = &ibuf->end;
+}
+
diff --git a/src/box/ibuf.h b/src/box/ibuf.h
new file mode 100644
index 000000000..7e0bba0d7
--- /dev/null
+++ b/src/box/ibuf.h
@@ -0,0 +1,76 @@
+#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 <stdlib.h>
+
+#include <trivia/util.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
+ * @param ibuf buffer used for allocation
+ * @param size allocated bytes
+ * @retval NULL on error, check diag.
+ */
+API_EXPORT void *
+box_ibuf_reserve(box_ibuf_t *ibuf, size_t size);
+
+/**
+ * Return pointers to read range pointers used [rpos..wpos)
+ * @param ibuf ibuf structure
+ * @param rpos where to place ibuf.rpos address
+ * @param rpos where to place ibuf.wpos address
+ */
+API_EXPORT void
+box_ibuf_read_range(box_ibuf_t *ibuf, char ***rpos, char ***wpos);
+
+/**
+ * Return pointers to write range pointers used [wpos..end)
+ * @param ibuf ibuf structure
+ * @param rpos where to place ibuf.rpos address
+ * @param rpos where to place ibuf.wpos address
+ */
+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 9c56686db..6d8138ff5 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 1c5723693..7a1c0c31d 100644
--- a/test/app-tap/module_api.c
+++ b/test/app-tap/module_api.c
@@ -164,6 +164,49 @@ test_toibuf(lua_State *L)
 	return 1;
 }
 
+static int
+test_box_ibuf(lua_State *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);
+	void *ptr = box_ibuf_reserve(&ibuf, 65536);
+	assert(ptr != NULL);
+	char **rpos;
+	char **wpos;
+	box_ibuf_read_range(&ibuf, &rpos, &wpos);
+
+	ptr = ibuf_alloc(&ibuf, 10);
+	assert(ptr != NULL);
+
+	assert(ibuf_used(&ibuf) == 10);
+	assert((*wpos - *rpos) == 10);
+
+	/* let be a little bit paranoid and double check */
+	box_ibuf_read_range(&ibuf, &rpos, &wpos);
+	assert((*wpos - *rpos) == 10);
+
+	ptr = ibuf_alloc(&ibuf, 10000);
+	assert(ptr);
+	assert(ibuf_used(&ibuf) == 10010);
+	assert((*wpos - *rpos) == 10010);
+
+	size_t unused = ibuf_unused(&ibuf);
+	char **end;
+	box_ibuf_write_range(&ibuf, &wpos, &end);
+	assert((*end - *wpos) == (ptrdiff_t)unused);
+
+	ibuf_reset(&ibuf);
+	assert(ibuf_used(&ibuf) == 0);
+	assert(*rpos == *wpos);
+
+	lua_pushboolean(L, 1);
+	return 1;
+}
+
 static int
 test_touint64(lua_State *L)
 {
@@ -1277,6 +1320,7 @@ luaopen_module_api(lua_State *L)
 		{"tuple_validate_def", test_tuple_validate_default},
 		{"tuple_validate_fmt", test_tuple_validate_formatted},
 		{"test_key_def_dup", test_key_def_dup},
+		{"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 c1aff6797..f91762e54 100755
--- a/test/app-tap/module_api.test.lua
+++ b/test/app-tap/module_api.test.lua
@@ -218,7 +218,7 @@ local function test_iscdata(test, module)
 end
 
 local test = require('tap').test("module_api", function(test)
-    test:plan(34)
+    test:plan(35)
     local status, module = pcall(require, 'module_api')
     test:is(status, true, "module")
     test:ok(status, "module is loaded")
-- 
2.20.1