From f4e7febf228532d95bf085bc7a8961612d777c4a Mon Sep 17 00:00:00 2001
From: Dhruba Borthakur <dhruba@dev3936.snc6.facebook.com>
Date: Tue, 21 Aug 2012 00:33:21 -0700
Subject: [PATCH] Record the version of the source repository that was used to
 build the leveldb library.

Summary: Record the version of the source that we are compiling. We keep a record of the git revision in util/version.cc. This source file is then built as a regular source file as part of the compilation process. One can run "strings executable_filename | grep _build_" to find the version of the source that we used to build the executable file.

Test Plan: none

Differential Revision: https://reviews.facebook.net/D4785
---
 Makefile              |  8 ++++++--
 build_detect_platform |  2 ++
 build_detect_version  | 25 +++++++++++++++++++++++++
 db/db_impl.cc         | 10 ++++++++++
 util/build_version.h  | 14 ++++++++++++++
 5 files changed, 57 insertions(+), 2 deletions(-)
 create mode 100755 build_detect_version
 create mode 100644 util/build_version.h

diff --git a/Makefile b/Makefile
index d937bce50..65600739d 100644
--- a/Makefile
+++ b/Makefile
@@ -60,6 +60,7 @@ TOOLS = \
 
 PROGRAMS = db_bench $(TESTS) $(TOOLS)
 BENCHMARKS = db_bench_sqlite3 db_bench_tree_db
+VERSIONFILE=util/build_version.cc
 
 LIBRARY = libleveldb.a
 MEMENVLIBRARY = libmemenv.a
@@ -83,13 +84,13 @@ $(SHARED1): $(SHARED3)
 	ln -fs $(SHARED3) $(SHARED1)
 endif
 
-all: $(SHARED) $(LIBRARY) $(THRIFTSERVER)
+all: $(VERSIONFILE) $(SHARED) $(LIBRARY) $(THRIFTSERVER)
 
 check: all $(PROGRAMS) $(TESTS) $(TOOLS)
 	for t in $(TESTS); do echo "***** Running $$t"; ./$$t || exit 1; done
 
 clean:
-	-rm -f $(PROGRAMS) $(BENCHMARKS) $(LIBRARY) $(SHARED) $(MEMENVLIBRARY) $(THRIFTSERVER) */*.o */*/*.o ios-x86/*/*.o ios-arm/*/*.o build_config.mk
+	-rm -f $(PROGRAMS) $(BENCHMARKS) $(LIBRARY) $(SHARED) $(MEMENVLIBRARY) $(THRIFTSERVER) */*.o */*/*.o ios-x86/*/*.o ios-arm/*/*.o build_config.mk $(VERSIONFILE)
 	-rm -rf ios-x86/* ios-arm/*
 
 $(LIBRARY): $(LIBOBJECTS)
@@ -178,6 +179,9 @@ manifest_dump: tools/manifest_dump.o $(LIBOBJECTS)
 filelock_test: util/filelock_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(CXX) util/filelock_test.o $(LIBOBJECTS) $(TESTHARNESS) -o $@ $(LDFLAGS)
 
+# recreate the version file with the latest git revision
+$(VERSIONFILE):	build_detect_version
+	$(shell ./build_detect_platform build_config.mk)
 
 ifeq ($(PLATFORM), IOS)
 # For iOS, create universal object files to be used on both the simulator and
diff --git a/build_detect_platform b/build_detect_platform
index dfd598d3d..ce33e2c92 100755
--- a/build_detect_platform
+++ b/build_detect_platform
@@ -96,6 +96,8 @@ case "$TARGET_OS" in
         exit 1
 esac
 
+./build_detect_version
+
 # We want to make a list of all cc files within util, db, table, and helpers
 # except for the test and benchmark files. By default, find will output a list
 # of all files matching either rule, so we need to append -print to make the
diff --git a/build_detect_version b/build_detect_version
new file mode 100755
index 000000000..ab56eadc6
--- /dev/null
+++ b/build_detect_version
@@ -0,0 +1,25 @@
+#!/bin/sh
+#
+# Record the version of the source that we are compiling.
+# We keep a record of the git revision in util/version.cc. This source file
+# is then built as a regular source file as part of the compilation process.
+# One can run "strings executable_filename | grep _build_" to find the version of
+# the source that we used to build the executable file.
+#
+
+# create git version file
+VFILE=util/build_version.cc
+
+# check to see if git is in the path
+which git > /dev/null
+
+if [ "$?" = 0 ]; then
+  git rev-parse HEAD | awk ' BEGIN {print "#include \"build_version.h\""} {print "const char * leveldb_build_git_sha = \"leveldb_build_git_sha:" $0"\";"} END {}' >  ${VFILE}
+else
+  echo "git not found"| awk ' BEGIN {print "#include \"build_version.h\""} {print "const char * leveldb_build_git_sha = \"leveldb_build_git_sha:git not found\";"} END {}' > ${VFILE}
+fi
+
+date | awk 'BEGIN {} {print "const char * leveldb_build_git_datetime = \"leveldb_build_git_datetime:"$0"\";"} END {} ' >> ${VFILE}
+echo "const char * leveldb_build_compile_date = __DATE__;" >> ${VFILE}
+echo "const char * leveldb_build_compile_time = __TIME__;" >> ${VFILE}
+
diff --git a/db/db_impl.cc b/db/db_impl.cc
index c4caae14c..1b5acb4bf 100644
--- a/db/db_impl.cc
+++ b/db/db_impl.cc
@@ -33,6 +33,7 @@
 #include "util/coding.h"
 #include "util/logging.h"
 #include "util/mutexlock.h"
+#include "util/build_version.h"
 
 namespace leveldb {
 
@@ -1544,4 +1545,13 @@ Status DestroyDB(const std::string& dbname, const Options& options) {
   return result;
 }
 
+//
+// A global method that can dump out the build version
+void printLeveldbBuildVersion() {
+  printf("Git sha %s", leveldb_build_git_sha);
+  printf("Git datetime %s", leveldb_build_git_datetime);
+  printf("Compile time %s", leveldb_build_compile_time);
+  printf("Compile date %s", leveldb_build_compile_date);
+}
+
 }  // namespace leveldb
diff --git a/util/build_version.h b/util/build_version.h
new file mode 100644
index 000000000..bcf869372
--- /dev/null
+++ b/util/build_version.h
@@ -0,0 +1,14 @@
+/*version.h*/
+#ifndef VERSION_H_
+#define VERSION_H_
+
+// these variables tell us about the git config and time
+extern const char* leveldb_build_git_sha;
+extern const char* leveldb_build_git_datetime;
+
+// these variables tell us when the compilation occured
+extern const char* leveldb_build_compile_time;
+extern const char* leveldb_build_compile_date;
+
+
+#endif /* VERSION_H_ */