[Tarantool-patches] [PATCH 2.X v4 4/4] 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
---
 src/CMakeLists.txt               |  1 +
 src/box/CMakeLists.txt           |  1 +
 src/box/ibuf.c                   | 65 +++++++++++++++++++++++++++++++
 src/box/ibuf.h                   | 67 ++++++++++++++++++++++++++++++++
 src/exports.h                    |  3 ++
 test/app-tap/module_api.c        | 44 +++++++++++++++++++++
 test/app-tap/module_api.test.lua |  2 +-
 7 files changed, 182 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..12b9f2781
--- /dev/null
+++ b/src/box/ibuf.c
@@ -0,0 +1,65 @@
+/*
+ * 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 <small/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)
+{
+	assert(ibuf != NULL);
+	if (ibuf == NULL)
+		return;
+	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)
+{
+	if (ibuf == NULL)
+		return;
+	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..d17f8f4b4
--- /dev/null
+++ b/src/box/ibuf.h
@@ -0,0 +1,67 @@
+#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
+ */
+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 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 a095416fe..e73ad6d72 100644
--- a/test/app-tap/module_api.c
+++ b/test/app-tap/module_api.c
@@ -164,6 +164,49 @@ test_checkibuf(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 ff251b338..33150d91e 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