Fix ldb segfault and use static libsnappy for all builds

Summary:
Link statically against snappy, using the gvfs one for facebook
environments, and the bundled one otherwise.

In addition, fix a few minor segfaults in ldb when it couldn't open the
database, and update .gitignore to include a few other build artifacts.

Test Plan: make check

Reviewers: dhruba

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D6855

.gitignore

@@ -6,3 +6,10 @@ build_config.mk
 *.so.*
 *_test
 db_bench
+db_stress
+ldb
+leveldb_server
+leveldb_shell
+manifest_dump
+sst_dump
+util/build_version.cc

build_detect_platform

@@ -165,7 +165,7 @@ EOF
 EOF
     if [ "$?" = 0 ]; then
         COMMON_FLAGS="$COMMON_FLAGS -DSNAPPY"
-        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS -lsnappy -L./snappy/libs"
+        PLATFORM_LDFLAGS="$PLATFORM_LDFLAGS ${SNAPPY_LDFLAGS:-./snappy/libs/libsnappy.a}"
     fi
 
     # Test whether zlib library is installed

fbcode.gcc471.sh

@@ -24,8 +24,8 @@ if test "$USE_HDFS"; then
 fi
 
 # location of snappy headers and libraries
-SNAPPY_INCLUDE=" -I ./snappy"
-SNAPPY_LIBS=" -L./snappy/libs"
+SNAPPY_INCLUDE=" -I $TOOLCHAIN_LIB_BASE/snappy/snappy-1.0.3/7518bbe/include"
+SNAPPY_LIBS=" $TOOLCHAIN_LIB_BASE/snappy/snappy-1.0.3/7518bbe/lib/libsnappy.a"
 
 # location of boost headers and libraries
 THRIFT_INCLUDE=" -I $TOOLCHAIN_LIB_BASE/boost/boost-1.48.0/bef9365/include -std=gnu++0x"
@@ -49,5 +49,6 @@ EXEC_LDFLAGS=" -Wl,--whole-archive $TOOLCHAIN_LIB_BASE/jemalloc/$TOOL_JEMALLOC/l
 EXEC_LDFLAGS+="-Wl,--no-whole-archive $TOOLCHAIN_LIB_BASE/libunwind/libunwind-20100812_experimental/91ddd43/lib/libunwind.a"
 EXEC_LDFLAGS+="$HDFSLIB $SNAPPY_LIBS $THRIFT_LIBS "
 EXEC_LDFLAGS_SHARED="$SNAPPY_LIBS $TOOLCHAIN_LIB_BASE/jemalloc/$TOOL_JEMALLOC/lib/libjemalloc.so"
+SNAPPY_LDFLAGS="$SNAPPY_LIBS"
 
-export CC CXX AR RANLIB CFLAGS EXEC_LDFLAGS EXEC_LDFLAGS_SHARED
+export CC CXX AR RANLIB CFLAGS EXEC_LDFLAGS EXEC_LDFLAGS_SHARED SNAPPY_LDFLAGS

util/ldb_cmd.cc

@@ -315,6 +315,9 @@ void ReduceDBLevels::DoCommand() {
   old_levels_ = old_level_num;
 
   OpenDB();
+  if (!db_) {
+    return;
+  }
   // Compact the whole DB to put all files to the highest level.
   fprintf(stdout, "Compacting the db...\n");
   db_->CompactRange(NULL, NULL);

util/ldb_cmd.h

@@ -44,10 +44,10 @@ public:
     case EXEC_SUCCEED:
       break;
     case EXEC_FAILED:
-      ret.append("Failed.");
+      ret.append("Failed: ");
       break;
     case EXEC_NOT_STARTED:
-      ret.append("Not started.");
+      ret.append("Not started: ");
     }
     if (!message_.empty()) {
       ret.append(message_);
@@ -134,6 +134,10 @@ public:
       OpenDB();
     }
 
+   if (!db_) {
+     return;
+   }
+
     DoCommand();
     if (exec_state_.IsNotStarted()) {
       exec_state_ = LDBCommandExecuteResult::SUCCEED("");