HADOOP-8901. GZip and Snappy support may not work without unversioned libraries. Contributed by Colin Patrick McCabe.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1398416 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -352,6 +352,9 @@ Release 2.0.3-alpha - Unreleased
     (Arpit Gupta via suresh)
 
 
+    HADOOP-8901. GZip and Snappy support may not work without unversioned
+    libraries (Colin Patrick McCabe via todd)
+
 Release 2.0.2-alpha - 2012-09-07 
 
   INCOMPATIBLE CHANGES

hadoop-common-project/hadoop-common/src/CMakeLists.txt

@@ -50,12 +50,41 @@ function(dual_output_directory TGT DIR)
     output_directory(${TGT}_static "${DIR}")
 endfunction(dual_output_directory TGT DIR)
 
+#
+# This macro alters the behavior of find_package and find_library.
+# It does this by setting the CMAKE_FIND_LIBRARY_SUFFIXES global variable. 
+# You should save that variable before calling this function and restore it
+# after you have accomplished your goal.
+#
+# The behavior is altered in two ways:
+# 1. We always find shared libraries, never static;
+# 2. We find shared libraries with the given version number.
+#
+# On Windows this function is a no-op.  Windows does not encode
+# version number information information into library path names.
+#
+macro(set_find_shared_library_version LVERS)
+    IF(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
+        # Mac OS uses .dylib
+        SET(CMAKE_FIND_LIBRARY_SUFFIXES ".${LVERS}.dylib")
+    ELSEIF(${CMAKE_SYSTEM_NAME} MATCHES "Windows")
+        # Windows doesn't support finding shared libraries by version.
+    ELSE()
+        # Most UNIX variants use .so
+        SET(CMAKE_FIND_LIBRARY_SUFFIXES ".so.${LVERS}")
+    ENDIF()
+endmacro(set_find_shared_library_version LVERS)
+
 if (NOT GENERATED_JAVAH)
     # Must identify where the generated headers have been placed
     MESSAGE(FATAL_ERROR "You must set the cmake variable GENERATED_JAVAH")
 endif (NOT GENERATED_JAVAH)
 find_package(JNI REQUIRED)
+
+SET(STORED_CMAKE_FIND_LIBRARY_SUFFIXES CMAKE_FIND_LIBRARY_SUFFIXES)
+set_find_shared_library_version("1")
 find_package(ZLIB REQUIRED)
+SET(CMAKE_FIND_LIBRARY_SUFFIXES STORED_CMAKE_FIND_LIBRARY_SUFFIXES)
 
 set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g -Wall -O2")
 set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D_REENTRANT -D_FILE_OFFSET_BITS=64")
@@ -69,10 +98,13 @@ INCLUDE(CheckCSourceCompiles)
 CHECK_FUNCTION_EXISTS(sync_file_range HAVE_SYNC_FILE_RANGE)
 CHECK_FUNCTION_EXISTS(posix_fadvise HAVE_POSIX_FADVISE)
 
+SET(STORED_CMAKE_FIND_LIBRARY_SUFFIXES CMAKE_FIND_LIBRARY_SUFFIXES)
+set_find_shared_library_version("1")
 find_library(SNAPPY_LIBRARY 
     NAMES snappy
     PATHS ${CUSTOM_SNAPPY_PREFIX} ${CUSTOM_SNAPPY_PREFIX}/lib
           ${CUSTOM_SNAPPY_PREFIX}/lib64 ${CUSTOM_SNAPPY_LIB})
+SET(CMAKE_FIND_LIBRARY_SUFFIXES STORED_CMAKE_FIND_LIBRARY_SUFFIXES)
 find_path(SNAPPY_INCLUDE_DIR 
     NAMES snappy.h
     PATHS ${CUSTOM_SNAPPY_PREFIX} ${CUSTOM_SNAPPY_PREFIX}/include