From 8b5895ff79896f5a644ed55f87d6f31a4a821012 Mon Sep 17 00:00:00 2001
From: Bhavik Sheth <bsheth@meta.com>
Date: Mon, 22 Jul 2024 16:01:35 -0700
Subject: [PATCH] 1720 - expose FAISS version field to c_api (#3635)

Summary:
Pull Request resolved: https://github.com/facebookresearch/faiss/pull/3635

Add a util function to return the version in the c api.

Reviewed By: ramilbakhshyiev, fxdawnn

Differential Revision: D59817407

fbshipit-source-id: ca805f8e04f554d0294ba9da8ec6dc7c31e91fe3
---
 faiss/Index.h         | 25 ++++++++++++++++++++-----
 faiss/utils/utils.cpp |  5 +++++
 faiss/utils/utils.h   |  3 +++
 tests/CMakeLists.txt  |  1 +
 tests/test_utils.cpp  | 19 +++++++++++++++++++
 5 files changed, 48 insertions(+), 5 deletions(-)
 create mode 100644 tests/test_utils.cpp

diff --git a/faiss/Index.h b/faiss/Index.h
index 3d1bdb996..f57140ec4 100644
--- a/faiss/Index.h
+++ b/faiss/Index.h
@@ -20,6 +20,18 @@
 #define FAISS_VERSION_MINOR 8
 #define FAISS_VERSION_PATCH 0
 
+// Macro to combine the version components into a single string
+#ifndef FAISS_STRINGIFY
+#define FAISS_STRINGIFY(ARG) #ARG
+#endif
+#ifndef FAISS_TOSTRING
+#define FAISS_TOSTRING(ARG) FAISS_STRINGIFY(ARG)
+#endif
+#define VERSION_STRING                                          \
+    FAISS_TOSTRING(FAISS_VERSION_MAJOR)                         \
+    "." FAISS_TOSTRING(FAISS_VERSION_MINOR) "." FAISS_TOSTRING( \
+            FAISS_VERSION_PATCH)
+
 /**
  * @namespace faiss
  *
@@ -38,8 +50,8 @@
 
 namespace faiss {
 
-/// Forward declarations see impl/AuxIndexStructures.h, impl/IDSelector.h and
-/// impl/DistanceComputer.h
+/// Forward declarations see impl/AuxIndexStructures.h, impl/IDSelector.h
+/// and impl/DistanceComputer.h
 struct IDSelector;
 struct RangeSearchResult;
 struct DistanceComputer;
@@ -56,7 +68,8 @@ struct SearchParameters {
     virtual ~SearchParameters() {}
 };
 
-/** Abstract structure for an index, supports adding vectors and searching them.
+/** Abstract structure for an index, supports adding vectors and searching
+ * them.
  *
  * All vectors provided at add or search time are 32-bit float arrays,
  * although the internal representation may vary.
@@ -154,7 +167,8 @@ struct Index {
 
     /** return the indexes of the k vectors closest to the query x.
      *
-     * This function is identical as search but only return labels of neighbors.
+     * This function is identical as search but only return labels of
+     * neighbors.
      * @param n           number of vectors
      * @param x           input vectors to search, size n * d
      * @param labels      output labels of the NNs, size n*k
@@ -179,7 +193,8 @@ struct Index {
      */
     virtual void reconstruct(idx_t key, float* recons) const;
 
-    /** Reconstruct several stored vectors (or an approximation if lossy coding)
+    /** Reconstruct several stored vectors (or an approximation if lossy
+     * coding)
      *
      * this function may not be defined for some indexes
      * @param n           number of vectors to reconstruct
diff --git a/faiss/utils/utils.cpp b/faiss/utils/utils.cpp
index dc6faddaf..bcb3c280b 100644
--- a/faiss/utils/utils.cpp
+++ b/faiss/utils/utils.cpp
@@ -7,6 +7,7 @@
 
 // -*- c++ -*-
 
+#include <faiss/Index.h>
 #include <faiss/utils/utils.h>
 
 #include <cassert>
@@ -129,6 +130,10 @@ std::string get_compile_options() {
     return options;
 }
 
+std::string get_version() {
+    return VERSION_STRING;
+}
+
 #ifdef _MSC_VER
 double getmillisecs() {
     LARGE_INTEGER ts;
diff --git a/faiss/utils/utils.h b/faiss/utils/utils.h
index e75207338..4d10a8c0f 100644
--- a/faiss/utils/utils.h
+++ b/faiss/utils/utils.h
@@ -37,6 +37,9 @@ std::string get_compile_options();
  * Get some stats about the system
  **************************************************/
 
+// Expose FAISS version as a string
+std::string get_version();
+
 /// ms elapsed since some arbitrary epoch
 double getmillisecs();
 
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 3980d7dd7..23d076a55 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -35,6 +35,7 @@ set(FAISS_TEST_SRC
   test_disable_pq_sdc_tables.cpp
   test_common_ivf_empty_index.cpp
   test_callback.cpp
+  test_utils.cpp
 )
 
 add_executable(faiss_test ${FAISS_TEST_SRC})
diff --git a/tests/test_utils.cpp b/tests/test_utils.cpp
new file mode 100644
index 000000000..793e29071
--- /dev/null
+++ b/tests/test_utils.cpp
@@ -0,0 +1,19 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <gtest/gtest.h>
+
+#include <faiss/Index.h>
+#include <faiss/utils/utils.h>
+
+TEST(TestUtils, get_version) {
+    std::string version = std::to_string(FAISS_VERSION_MAJOR) + "." +
+            std::to_string(FAISS_VERSION_MINOR) + "." +
+            std::to_string(FAISS_VERSION_PATCH);
+
+    EXPECT_EQ(version, faiss::get_version());
+}