Add LEVELDB_EXPORT macro to export public symbols.

gcc defaults to exporting all symbols, but other linkers do not. Adding
the LEVELDB_EXPORT macro allows a project to set LEVELDB_SHARED_LIBRARY
when building/linking with leveldb as a shared library.

This is to allow leveldb to be created as a shared library on all
platforms support by Chrome and enables a fix for
https://bugs.chromium.org/p/chromium/issues/detail?id=764810.

This also has the benefit of reducing the shared library size from
418863 to 380367 bytes (64-bit Linux).

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=171037148

Makefile

@@ -81,7 +81,7 @@ else
 STATIC_OUTDIR=out-static
 SHARED_OUTDIR=out-shared
 STATIC_PROGRAMS := $(addprefix $(STATIC_OUTDIR)/, $(PROGNAMES))
-SHARED_PROGRAMS := $(addprefix $(SHARED_OUTDIR)/, db_bench)
+SHARED_PROGRAMS := $(addprefix $(SHARED_OUTDIR)/, db_bench c_test)
 endif
 
 STATIC_LIBOBJECTS := $(addprefix $(STATIC_OUTDIR)/, $(SOURCES:.cc=.o))
@@ -98,6 +98,7 @@ SHARED_MEMENVOBJECTS := $(addprefix $(SHARED_OUTDIR)/, $(MEMENV_SOURCES:.cc=.o))
 
 TESTUTIL := $(STATIC_OUTDIR)/util/testutil.o
 TESTHARNESS := $(STATIC_OUTDIR)/util/testharness.o $(TESTUTIL)
+TEST_STATIC_OBJS := $(STATIC_OUTDIR)/port/port_posix.o $(STATIC_OUTDIR)/port/port_posix_sse.o $(STATIC_OUTDIR)/util/crc32c.o $(STATIC_OUTDIR)/util/histogram.o
 
 STATIC_TESTOBJS := $(addprefix $(STATIC_OUTDIR)/, $(addsuffix .o, $(TESTS)))
 STATIC_UTILOBJS := $(addprefix $(STATIC_OUTDIR)/, $(addsuffix .o, $(UTILS)))
@@ -112,6 +113,8 @@ ifneq ($(PLATFORM_SHARED_EXT),)
 
 # Many leveldb test apps use non-exported API's. Only build a subset for testing.
 SHARED_ALLOBJS := $(SHARED_LIBOBJECTS) $(SHARED_MEMENVOBJECTS) $(TESTHARNESS)
+SHARED_CXXFLAGS += -DLEVELDB_SHARED_LIBRARY
+SHARED_BUILD_CXXFLAGS += $(SHARED_CXXFLAGS) -DLEVELDB_COMPILE_LIBRARY
 
 ifneq ($(PLATFORM_SHARED_VERSIONED),true)
 SHARED_LIB1 = libleveldb.$(PLATFORM_SHARED_EXT)
@@ -386,13 +389,20 @@ $(STATIC_OUTDIR)/write_batch_test:db/write_batch_test.cc $(STATIC_LIBOBJECTS) $(
 $(STATIC_OUTDIR)/memenv_test:$(STATIC_OUTDIR)/helpers/memenv/memenv_test.o $(STATIC_OUTDIR)/libmemenv.a $(STATIC_OUTDIR)/libleveldb.a $(TESTHARNESS)
 	$(XCRUN) $(CXX) $(LDFLAGS) $(STATIC_OUTDIR)/helpers/memenv/memenv_test.o $(STATIC_OUTDIR)/libmemenv.a $(STATIC_OUTDIR)/libleveldb.a $(TESTHARNESS) -o $@ $(LIBS)
 
-$(SHARED_OUTDIR)/db_bench:$(SHARED_OUTDIR)/db/db_bench.o $(SHARED_LIBS) $(TESTUTIL)
-	$(XCRUN) $(CXX) $(LDFLAGS) $(CXXFLAGS) $(PLATFORM_SHARED_CFLAGS) $(SHARED_OUTDIR)/db/db_bench.o $(TESTUTIL) $(SHARED_OUTDIR)/$(SHARED_LIB3) -o $@ $(LIBS)
+$(SHARED_OUTDIR)/db_bench:$(SHARED_OUTDIR)/db/db_bench.o $(SHARED_LIBS) $(TESTUTIL) $(TEST_STATIC_OBJS)
+	$(XCRUN) $(CXX) $(LDFLAGS) $(CXXFLAGS) $(PLATFORM_SHARED_CFLAGS) $(SHARED_CXXFLAGS) $(SHARED_OUTDIR)/db/db_bench.o $(TESTUTIL) $(TEST_STATIC_OBJS) $(SHARED_OUTDIR)/$(SHARED_LIB3) -o $@ $(LIBS)
 
-.PHONY: run-shared
-run-shared: $(SHARED_OUTDIR)/db_bench
+$(SHARED_OUTDIR)/c_test:$(SHARED_OUTDIR)/db/c_test.o $(SHARED_LIBS) $(TESTUTIL) $(TEST_STATIC_OBJS)
+	$(XCRUN) $(CXX) $(LDFLAGS) $(CXXFLAGS) $(PLATFORM_SHARED_CFLAGS) $(SHARED_CXXFLAGS) $(SHARED_OUTDIR)/db/c_test.o $(TESTUTIL) $(TEST_STATIC_OBJS) $(SHARED_OUTDIR)/$(SHARED_LIB3) -o $@ $(LIBS)
+
+.PHONY: run-shared-db_bench
+run-shared-db_bench: $(SHARED_OUTDIR)/db_bench
 	LD_LIBRARY_PATH=$(SHARED_OUTDIR) $(SHARED_OUTDIR)/db_bench
 
+.PHONY: run-shared-c_test
+run-shared-c_test: $(SHARED_OUTDIR)/c_test
+	LD_LIBRARY_PATH=$(SHARED_OUTDIR) $(SHARED_OUTDIR)/c_test
+
 $(SIMULATOR_OUTDIR)/%.o: %.cc
 	xcrun -sdk iphonesimulator $(CXX) $(CXXFLAGS) $(SIMULATOR_CFLAGS) -c $< -o $@
 
@@ -412,13 +422,13 @@ $(STATIC_OUTDIR)/%.o: %.c
 	$(CC) $(CFLAGS) -c $< -o $@
 
 $(SHARED_OUTDIR)/%.o: %.cc
-	$(CXX) $(CXXFLAGS) $(PLATFORM_SHARED_CFLAGS) -c $< -o $@
+	$(CXX) $(CXXFLAGS) $(SHARED_BUILD_CXXFLAGS) $(PLATFORM_SHARED_CFLAGS) -c $< -o $@
 
 $(SHARED_OUTDIR)/%.o: %.c
-	$(CC) $(CFLAGS) $(PLATFORM_SHARED_CFLAGS) -c $< -o $@
+	$(CC) $(CFLAGS) $(SHARED_BUILD_CXXFLAGS) $(PLATFORM_SHARED_CFLAGS) -c $< -o $@
 
 $(STATIC_OUTDIR)/port/port_posix_sse.o: port/port_posix_sse.cc
-	$(CXX) $(CXXFLAGS) $(PLATFORM_SSEFLAGS) -c $< -o $@
+	$(CXX) $(CXXFLAGS) $(SHARED_BUILD_CXXFLAGS) $(PLATFORM_SSEFLAGS) -c $< -o $@
 
 $(SHARED_OUTDIR)/port/port_posix_sse.o: port/port_posix_sse.cc
-	$(CXX) $(CXXFLAGS) $(PLATFORM_SHARED_CFLAGS) $(PLATFORM_SSEFLAGS) -c $< -o $@
+	$(CXX) $(CXXFLAGS) $(SHARED_BUILD_CXXFLAGS) $(PLATFORM_SHARED_CFLAGS) $(PLATFORM_SSEFLAGS) -c $< -o $@

build_detect_platform

@@ -61,7 +61,7 @@ PLATFORM_LDFLAGS=
 PLATFORM_LIBS=
 PLATFORM_SHARED_EXT="so"
 PLATFORM_SHARED_LDFLAGS="-shared -Wl,-soname -Wl,"
-PLATFORM_SHARED_CFLAGS="-fPIC"
+PLATFORM_SHARED_CFLAGS="-fPIC -fvisibility=hidden"
 PLATFORM_SHARED_VERSIONED=true
 PLATFORM_SSEFLAGS=
 

include/leveldb/c.h

@@ -47,6 +47,7 @@ extern "C" {
 #include <stdarg.h>
 #include <stddef.h>
 #include <stdint.h>
+#include "leveldb/export.h"
 
 /* Exported types */
 
@@ -69,204 +70,178 @@ typedef struct leveldb_writeoptions_t  leveldb_writeoptions_t;
 
 /* DB operations */
 
-extern leveldb_t* leveldb_open(
-    const leveldb_options_t* options,
-    const char* name,
-    char** errptr);
+LEVELDB_EXPORT leveldb_t* leveldb_open(const leveldb_options_t* options,
+                                       const char* name, char** errptr);
 
-extern void leveldb_close(leveldb_t* db);
+LEVELDB_EXPORT void leveldb_close(leveldb_t* db);
 
-extern void leveldb_put(
-    leveldb_t* db,
-    const leveldb_writeoptions_t* options,
-    const char* key, size_t keylen,
-    const char* val, size_t vallen,
-    char** errptr);
+LEVELDB_EXPORT void leveldb_put(leveldb_t* db,
+                                const leveldb_writeoptions_t* options,
+                                const char* key, size_t keylen, const char* val,
+                                size_t vallen, char** errptr);
 
-extern void leveldb_delete(
-    leveldb_t* db,
-    const leveldb_writeoptions_t* options,
-    const char* key, size_t keylen,
-    char** errptr);
+LEVELDB_EXPORT void leveldb_delete(leveldb_t* db,
+                                   const leveldb_writeoptions_t* options,
+                                   const char* key, size_t keylen,
+                                   char** errptr);
 
-extern void leveldb_write(
-    leveldb_t* db,
-    const leveldb_writeoptions_t* options,
-    leveldb_writebatch_t* batch,
-    char** errptr);
+LEVELDB_EXPORT void leveldb_write(leveldb_t* db,
+                                  const leveldb_writeoptions_t* options,
+                                  leveldb_writebatch_t* batch, char** errptr);
 
 /* Returns NULL if not found.  A malloc()ed array otherwise.
    Stores the length of the array in *vallen. */
-extern char* leveldb_get(
-    leveldb_t* db,
-    const leveldb_readoptions_t* options,
-    const char* key, size_t keylen,
-    size_t* vallen,
-    char** errptr);
+LEVELDB_EXPORT char* leveldb_get(leveldb_t* db,
+                                 const leveldb_readoptions_t* options,
+                                 const char* key, size_t keylen, size_t* vallen,
+                                 char** errptr);
 
-extern leveldb_iterator_t* leveldb_create_iterator(
-    leveldb_t* db,
-    const leveldb_readoptions_t* options);
+LEVELDB_EXPORT leveldb_iterator_t* leveldb_create_iterator(
+    leveldb_t* db, const leveldb_readoptions_t* options);
 
-extern const leveldb_snapshot_t* leveldb_create_snapshot(
-    leveldb_t* db);
+LEVELDB_EXPORT const leveldb_snapshot_t* leveldb_create_snapshot(leveldb_t* db);
 
-extern void leveldb_release_snapshot(
-    leveldb_t* db,
-    const leveldb_snapshot_t* snapshot);
+LEVELDB_EXPORT void leveldb_release_snapshot(
+    leveldb_t* db, const leveldb_snapshot_t* snapshot);
 
 /* Returns NULL if property name is unknown.
    Else returns a pointer to a malloc()-ed null-terminated value. */
-extern char* leveldb_property_value(
-    leveldb_t* db,
-    const char* propname);
-
-extern void leveldb_approximate_sizes(
-    leveldb_t* db,
-    int num_ranges,
-    const char* const* range_start_key, const size_t* range_start_key_len,
-    const char* const* range_limit_key, const size_t* range_limit_key_len,
-    uint64_t* sizes);
-
-extern void leveldb_compact_range(
-    leveldb_t* db,
-    const char* start_key, size_t start_key_len,
-    const char* limit_key, size_t limit_key_len);
+LEVELDB_EXPORT char* leveldb_property_value(leveldb_t* db,
+                                            const char* propname);
+
+LEVELDB_EXPORT void leveldb_approximate_sizes(
+    leveldb_t* db, int num_ranges, const char* const* range_start_key,
+    const size_t* range_start_key_len, const char* const* range_limit_key,
+    const size_t* range_limit_key_len, uint64_t* sizes);
+
+LEVELDB_EXPORT void leveldb_compact_range(leveldb_t* db, const char* start_key,
+                                          size_t start_key_len,
+                                          const char* limit_key,
+                                          size_t limit_key_len);
 
 /* Management operations */
 
-extern void leveldb_destroy_db(
-    const leveldb_options_t* options,
-    const char* name,
-    char** errptr);
+LEVELDB_EXPORT void leveldb_destroy_db(const leveldb_options_t* options,
+                                       const char* name, char** errptr);
 
-extern void leveldb_repair_db(
-    const leveldb_options_t* options,
-    const char* name,
-    char** errptr);
+LEVELDB_EXPORT void leveldb_repair_db(const leveldb_options_t* options,
+                                      const char* name, char** errptr);
 
 /* Iterator */
 
-extern void leveldb_iter_destroy(leveldb_iterator_t*);
-extern unsigned char leveldb_iter_valid(const leveldb_iterator_t*);
-extern void leveldb_iter_seek_to_first(leveldb_iterator_t*);
-extern void leveldb_iter_seek_to_last(leveldb_iterator_t*);
-extern void leveldb_iter_seek(leveldb_iterator_t*, const char* k, size_t klen);
-extern void leveldb_iter_next(leveldb_iterator_t*);
-extern void leveldb_iter_prev(leveldb_iterator_t*);
-extern const char* leveldb_iter_key(const leveldb_iterator_t*, size_t* klen);
-extern const char* leveldb_iter_value(const leveldb_iterator_t*, size_t* vlen);
-extern void leveldb_iter_get_error(const leveldb_iterator_t*, char** errptr);
+LEVELDB_EXPORT void leveldb_iter_destroy(leveldb_iterator_t*);
+LEVELDB_EXPORT unsigned char leveldb_iter_valid(const leveldb_iterator_t*);
+LEVELDB_EXPORT void leveldb_iter_seek_to_first(leveldb_iterator_t*);
+LEVELDB_EXPORT void leveldb_iter_seek_to_last(leveldb_iterator_t*);
+LEVELDB_EXPORT void leveldb_iter_seek(leveldb_iterator_t*, const char* k,
+                                      size_t klen);
+LEVELDB_EXPORT void leveldb_iter_next(leveldb_iterator_t*);
+LEVELDB_EXPORT void leveldb_iter_prev(leveldb_iterator_t*);
+LEVELDB_EXPORT const char* leveldb_iter_key(const leveldb_iterator_t*,
+                                            size_t* klen);
+LEVELDB_EXPORT const char* leveldb_iter_value(const leveldb_iterator_t*,
+                                              size_t* vlen);
+LEVELDB_EXPORT void leveldb_iter_get_error(const leveldb_iterator_t*,
+                                           char** errptr);
 
 /* Write batch */
 
-extern leveldb_writebatch_t* leveldb_writebatch_create();
-extern void leveldb_writebatch_destroy(leveldb_writebatch_t*);
-extern void leveldb_writebatch_clear(leveldb_writebatch_t*);
-extern void leveldb_writebatch_put(
-    leveldb_writebatch_t*,
-    const char* key, size_t klen,
-    const char* val, size_t vlen);
-extern void leveldb_writebatch_delete(
-    leveldb_writebatch_t*,
-    const char* key, size_t klen);
-extern void leveldb_writebatch_iterate(
-    leveldb_writebatch_t*,
-    void* state,
+LEVELDB_EXPORT leveldb_writebatch_t* leveldb_writebatch_create();
+LEVELDB_EXPORT void leveldb_writebatch_destroy(leveldb_writebatch_t*);
+LEVELDB_EXPORT void leveldb_writebatch_clear(leveldb_writebatch_t*);
+LEVELDB_EXPORT void leveldb_writebatch_put(leveldb_writebatch_t*,
+                                           const char* key, size_t klen,
+                                           const char* val, size_t vlen);
+LEVELDB_EXPORT void leveldb_writebatch_delete(leveldb_writebatch_t*,
+                                              const char* key, size_t klen);
+LEVELDB_EXPORT void leveldb_writebatch_iterate(
+    leveldb_writebatch_t*, void* state,
     void (*put)(void*, const char* k, size_t klen, const char* v, size_t vlen),
     void (*deleted)(void*, const char* k, size_t klen));
 
 /* Options */
 
-extern leveldb_options_t* leveldb_options_create();
-extern void leveldb_options_destroy(leveldb_options_t*);
-extern void leveldb_options_set_comparator(
-    leveldb_options_t*,
-    leveldb_comparator_t*);
-extern void leveldb_options_set_filter_policy(
-    leveldb_options_t*,
-    leveldb_filterpolicy_t*);
-extern void leveldb_options_set_create_if_missing(
-    leveldb_options_t*, unsigned char);
-extern void leveldb_options_set_error_if_exists(
-    leveldb_options_t*, unsigned char);
-extern void leveldb_options_set_paranoid_checks(
-    leveldb_options_t*, unsigned char);
-extern void leveldb_options_set_env(leveldb_options_t*, leveldb_env_t*);
-extern void leveldb_options_set_info_log(leveldb_options_t*, leveldb_logger_t*);
-extern void leveldb_options_set_write_buffer_size(leveldb_options_t*, size_t);
-extern void leveldb_options_set_max_open_files(leveldb_options_t*, int);
-extern void leveldb_options_set_cache(leveldb_options_t*, leveldb_cache_t*);
-extern void leveldb_options_set_block_size(leveldb_options_t*, size_t);
-extern void leveldb_options_set_block_restart_interval(leveldb_options_t*, int);
+LEVELDB_EXPORT leveldb_options_t* leveldb_options_create();
+LEVELDB_EXPORT void leveldb_options_destroy(leveldb_options_t*);
+LEVELDB_EXPORT void leveldb_options_set_comparator(leveldb_options_t*,
+                                                   leveldb_comparator_t*);
+LEVELDB_EXPORT void leveldb_options_set_filter_policy(leveldb_options_t*,
+                                                      leveldb_filterpolicy_t*);
+LEVELDB_EXPORT void leveldb_options_set_create_if_missing(leveldb_options_t*,
+                                                          unsigned char);
+LEVELDB_EXPORT void leveldb_options_set_error_if_exists(leveldb_options_t*,
+                                                        unsigned char);
+LEVELDB_EXPORT void leveldb_options_set_paranoid_checks(leveldb_options_t*,
+                                                        unsigned char);
+LEVELDB_EXPORT void leveldb_options_set_env(leveldb_options_t*, leveldb_env_t*);
+LEVELDB_EXPORT void leveldb_options_set_info_log(leveldb_options_t*,
+                                                 leveldb_logger_t*);
+LEVELDB_EXPORT void leveldb_options_set_write_buffer_size(leveldb_options_t*,
+                                                          size_t);
+LEVELDB_EXPORT void leveldb_options_set_max_open_files(leveldb_options_t*, int);
+LEVELDB_EXPORT void leveldb_options_set_cache(leveldb_options_t*,
+                                              leveldb_cache_t*);
+LEVELDB_EXPORT void leveldb_options_set_block_size(leveldb_options_t*, size_t);
+LEVELDB_EXPORT void leveldb_options_set_block_restart_interval(
+    leveldb_options_t*, int);
 
 enum {
   leveldb_no_compression = 0,
   leveldb_snappy_compression = 1
 };
-extern void leveldb_options_set_compression(leveldb_options_t*, int);
+LEVELDB_EXPORT void leveldb_options_set_compression(leveldb_options_t*, int);
 
 /* Comparator */
 
-extern leveldb_comparator_t* leveldb_comparator_create(
-    void* state,
-    void (*destructor)(void*),
-    int (*compare)(
-        void*,
-        const char* a, size_t alen,
-        const char* b, size_t blen),
+LEVELDB_EXPORT leveldb_comparator_t* leveldb_comparator_create(
+    void* state, void (*destructor)(void*),
+    int (*compare)(void*, const char* a, size_t alen, const char* b,
+                   size_t blen),
     const char* (*name)(void*));
-extern void leveldb_comparator_destroy(leveldb_comparator_t*);
+LEVELDB_EXPORT void leveldb_comparator_destroy(leveldb_comparator_t*);
 
 /* Filter policy */
 
-extern leveldb_filterpolicy_t* leveldb_filterpolicy_create(
-    void* state,
-    void (*destructor)(void*),
-    char* (*create_filter)(
-        void*,
-        const char* const* key_array, const size_t* key_length_array,
-        int num_keys,
-        size_t* filter_length),
-    unsigned char (*key_may_match)(
-        void*,
-        const char* key, size_t length,
-        const char* filter, size_t filter_length),
+LEVELDB_EXPORT leveldb_filterpolicy_t* leveldb_filterpolicy_create(
+    void* state, void (*destructor)(void*),
+    char* (*create_filter)(void*, const char* const* key_array,
+                           const size_t* key_length_array, int num_keys,
+                           size_t* filter_length),
+    unsigned char (*key_may_match)(void*, const char* key, size_t length,
+                                   const char* filter, size_t filter_length),
     const char* (*name)(void*));
-extern void leveldb_filterpolicy_destroy(leveldb_filterpolicy_t*);
+LEVELDB_EXPORT void leveldb_filterpolicy_destroy(leveldb_filterpolicy_t*);
 
-extern leveldb_filterpolicy_t* leveldb_filterpolicy_create_bloom(
+LEVELDB_EXPORT leveldb_filterpolicy_t* leveldb_filterpolicy_create_bloom(
     int bits_per_key);
 
 /* Read options */
 
-extern leveldb_readoptions_t* leveldb_readoptions_create();
-extern void leveldb_readoptions_destroy(leveldb_readoptions_t*);
-extern void leveldb_readoptions_set_verify_checksums(
-    leveldb_readoptions_t*,
-    unsigned char);
-extern void leveldb_readoptions_set_fill_cache(
+LEVELDB_EXPORT leveldb_readoptions_t* leveldb_readoptions_create();
+LEVELDB_EXPORT void leveldb_readoptions_destroy(leveldb_readoptions_t*);
+LEVELDB_EXPORT void leveldb_readoptions_set_verify_checksums(
     leveldb_readoptions_t*, unsigned char);
-extern void leveldb_readoptions_set_snapshot(
-    leveldb_readoptions_t*,
-    const leveldb_snapshot_t*);
+LEVELDB_EXPORT void leveldb_readoptions_set_fill_cache(leveldb_readoptions_t*,
+                                                       unsigned char);
+LEVELDB_EXPORT void leveldb_readoptions_set_snapshot(leveldb_readoptions_t*,
+                                                     const leveldb_snapshot_t*);
 
 /* Write options */
 
-extern leveldb_writeoptions_t* leveldb_writeoptions_create();
-extern void leveldb_writeoptions_destroy(leveldb_writeoptions_t*);
-extern void leveldb_writeoptions_set_sync(
-    leveldb_writeoptions_t*, unsigned char);
+LEVELDB_EXPORT leveldb_writeoptions_t* leveldb_writeoptions_create();
+LEVELDB_EXPORT void leveldb_writeoptions_destroy(leveldb_writeoptions_t*);
+LEVELDB_EXPORT void leveldb_writeoptions_set_sync(leveldb_writeoptions_t*,
+                                                  unsigned char);
 
 /* Cache */
 
-extern leveldb_cache_t* leveldb_cache_create_lru(size_t capacity);
-extern void leveldb_cache_destroy(leveldb_cache_t* cache);
+LEVELDB_EXPORT leveldb_cache_t* leveldb_cache_create_lru(size_t capacity);
+LEVELDB_EXPORT void leveldb_cache_destroy(leveldb_cache_t* cache);
 
 /* Env */
 
-extern leveldb_env_t* leveldb_create_default_env();
-extern void leveldb_env_destroy(leveldb_env_t*);
+LEVELDB_EXPORT leveldb_env_t* leveldb_create_default_env();
+LEVELDB_EXPORT void leveldb_env_destroy(leveldb_env_t*);
 
 /* Utility */
 
@@ -275,13 +250,13 @@ extern void leveldb_env_destroy(leveldb_env_t*);
    in this file.  Note that in certain cases (typically on Windows), you
    may need to call this routine instead of free(ptr) to dispose of
    malloc()-ed memory returned by this library. */
-extern void leveldb_free(void* ptr);
+LEVELDB_EXPORT void leveldb_free(void* ptr);
 
 /* Return the major version number for this release. */
-extern int leveldb_major_version();
+LEVELDB_EXPORT int leveldb_major_version();
 
 /* Return the minor version number for this release. */
-extern int leveldb_minor_version();
+LEVELDB_EXPORT int leveldb_minor_version();
 
 #ifdef __cplusplus
 }  /* end extern "C" */

include/leveldb/cache.h

@@ -19,17 +19,18 @@
 #define STORAGE_LEVELDB_INCLUDE_CACHE_H_
 
 #include <stdint.h>
+#include "leveldb/export.h"
 #include "leveldb/slice.h"
 
 namespace leveldb {
 
-class Cache;
+class LEVELDB_EXPORT Cache;
 
 // Create a new cache with a fixed size capacity.  This implementation
 // of Cache uses a least-recently-used eviction policy.
-extern Cache* NewLRUCache(size_t capacity);
+LEVELDB_EXPORT Cache* NewLRUCache(size_t capacity);
 
-class Cache {
+class LEVELDB_EXPORT Cache {
  public:
   Cache() { }
 

include/leveldb/comparator.h

@@ -6,6 +6,7 @@
 #define STORAGE_LEVELDB_INCLUDE_COMPARATOR_H_
 
 #include <string>
+#include "leveldb/export.h"
 
 namespace leveldb {
 
@@ -15,7 +16,7 @@ class Slice;
 // used as keys in an sstable or a database.  A Comparator implementation
 // must be thread-safe since leveldb may invoke its methods concurrently
 // from multiple threads.
-class Comparator {
+class LEVELDB_EXPORT Comparator {
  public:
   virtual ~Comparator();
 
@@ -56,7 +57,7 @@ class Comparator {
 // Return a builtin comparator that uses lexicographic byte-wise
 // ordering.  The result remains the property of this module and
 // must not be deleted.
-extern const Comparator* BytewiseComparator();
+LEVELDB_EXPORT const Comparator* BytewiseComparator();
 
 }  // namespace leveldb
 

include/leveldb/db.h

@@ -7,6 +7,7 @@
 
 #include <stdint.h>
 #include <stdio.h>
+#include "leveldb/export.h"
 #include "leveldb/iterator.h"
 #include "leveldb/options.h"
 
@@ -24,13 +25,13 @@ class WriteBatch;
 // Abstract handle to particular state of a DB.
 // A Snapshot is an immutable object and can therefore be safely
 // accessed from multiple threads without any external synchronization.
-class Snapshot {
+class LEVELDB_EXPORT Snapshot {
  protected:
   virtual ~Snapshot();
 };
 
 // A range of keys
-struct Range {
+struct LEVELDB_EXPORT Range {
   Slice start;          // Included in the range
   Slice limit;          // Not included in the range
 
@@ -41,7 +42,7 @@ struct Range {
 // A DB is a persistent ordered map from keys to values.
 // A DB is safe for concurrent access from multiple threads without
 // any external synchronization.
-class DB {
+class LEVELDB_EXPORT DB {
  public:
   // Open the database with the specified "name".
   // Stores a pointer to a heap-allocated database in *dbptr and returns
@@ -150,13 +151,15 @@ class DB {
 
 // Destroy the contents of the specified database.
 // Be very careful using this method.
-Status DestroyDB(const std::string& name, const Options& options);
+LEVELDB_EXPORT Status DestroyDB(const std::string& name,
+                                const Options& options);
 
 // If a DB cannot be opened, you may attempt to call this method to
 // resurrect as much of the contents of the database as possible.
 // Some data may be lost, so be careful when calling this function
 // on a database that contains important information.
-Status RepairDB(const std::string& dbname, const Options& options);
+LEVELDB_EXPORT Status RepairDB(const std::string& dbname,
+                               const Options& options);
 
 }  // namespace leveldb
 

include/leveldb/dumpfile.h

@@ -7,6 +7,7 @@
 
 #include <string>
 #include "leveldb/env.h"
+#include "leveldb/export.h"
 #include "leveldb/status.h"
 
 namespace leveldb {
@@ -18,7 +19,8 @@ namespace leveldb {
 //
 // Returns a non-OK result if fname does not name a leveldb storage
 // file, or if the file cannot be read.
-Status DumpFile(Env* env, const std::string& fname, WritableFile* dst);
+LEVELDB_EXPORT Status DumpFile(Env* env, const std::string& fname,
+                               WritableFile* dst);
 
 }  // namespace leveldb
 

include/leveldb/env.h

@@ -13,10 +13,11 @@
 #ifndef STORAGE_LEVELDB_INCLUDE_ENV_H_
 #define STORAGE_LEVELDB_INCLUDE_ENV_H_
 
-#include <string>
-#include <vector>
 #include <stdarg.h>
 #include <stdint.h>
+#include <string>
+#include <vector>
+#include "leveldb/export.h"
 #include "leveldb/status.h"
 
 namespace leveldb {
@@ -28,7 +29,7 @@ class SequentialFile;
 class Slice;
 class WritableFile;
 
-class Env {
+class LEVELDB_EXPORT Env {
  public:
   Env() { }
   virtual ~Env();
@@ -169,7 +170,7 @@ class Env {
 };
 
 // A file abstraction for reading sequentially through a file
-class SequentialFile {
+class LEVELDB_EXPORT SequentialFile {
  public:
   SequentialFile() { }
   virtual ~SequentialFile();
@@ -200,7 +201,7 @@ class SequentialFile {
 };
 
 // A file abstraction for randomly reading the contents of a file.
-class RandomAccessFile {
+class LEVELDB_EXPORT RandomAccessFile {
  public:
   RandomAccessFile() { }
   virtual ~RandomAccessFile();
@@ -226,7 +227,7 @@ class RandomAccessFile {
 // A file abstraction for sequential writing.  The implementation
 // must provide buffering since callers may append small fragments
 // at a time to the file.
-class WritableFile {
+class LEVELDB_EXPORT WritableFile {
  public:
   WritableFile() { }
   virtual ~WritableFile();
@@ -243,7 +244,7 @@ class WritableFile {
 };
 
 // An interface for writing log messages.
-class Logger {
+class LEVELDB_EXPORT Logger {
  public:
   Logger() { }
   virtual ~Logger();
@@ -259,7 +260,7 @@ class Logger {
 
 
 // Identifies a locked file.
-class FileLock {
+class LEVELDB_EXPORT FileLock {
  public:
   FileLock() { }
   virtual ~FileLock();
@@ -277,17 +278,17 @@ extern void Log(Logger* info_log, const char* format, ...)
     ;
 
 // A utility routine: write "data" to the named file.
-extern Status WriteStringToFile(Env* env, const Slice& data,
-                                const std::string& fname);
+LEVELDB_EXPORT Status WriteStringToFile(Env* env, const Slice& data,
+                                        const std::string& fname);
 
 // A utility routine: read contents of named file into *data
-extern Status ReadFileToString(Env* env, const std::string& fname,
-                               std::string* data);
+LEVELDB_EXPORT Status ReadFileToString(Env* env, const std::string& fname,
+                                       std::string* data);
 
 // An implementation of Env that forwards all calls to another Env.
 // May be useful to clients who wish to override just part of the
 // functionality of another Env.
-class EnvWrapper : public Env {
+class LEVELDB_EXPORT EnvWrapper : public Env {
  public:
   // Initialize an EnvWrapper that delegates all calls to *t
   explicit EnvWrapper(Env* t) : target_(t) { }

include/leveldb/export.h

@@ -0,0 +1,33 @@
+// Copyright (c) 2017 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#ifndef STORAGE_LEVELDB_INCLUDE_EXPORT_H_
+#define STORAGE_LEVELDB_INCLUDE_EXPORT_H_
+
+#if !defined(LEVELDB_EXPORT)
+
+#if defined(LEVELDB_SHARED_LIBRARY)
+#if defined(OS_WIN)
+
+#if defined(LEVELDB_COMPILE_LIBRARY)
+#define LEVELDB_EXPORT __declspec(dllexport)
+#else
+#define LEVELDB_EXPORT __declspec(dllimport)
+#endif  // defined(LEVELDB_COMPILE_LIBRARY)
+
+#else  // defined(OS_WIN)
+#if defined(LEVELDB_COMPILE_LIBRARY)
+#define LEVELDB_EXPORT __attribute__((visibility("default")))
+#else
+#define LEVELDB_EXPORT
+#endif
+#endif  // defined(OS_WIN)
+
+#else  // defined(LEVELDB_SHARED_LIBRARY)
+#define LEVELDB_EXPORT
+#endif
+
+#endif  // !defined(LEVELDB_EXPORT)
+
+#endif  // STORAGE_LEVELDB_INCLUDE_EXPORT_H_

include/leveldb/filter_policy.h

@@ -17,12 +17,13 @@
 #define STORAGE_LEVELDB_INCLUDE_FILTER_POLICY_H_
 
 #include <string>
+#include "leveldb/export.h"
 
 namespace leveldb {
 
 class Slice;
 
-class FilterPolicy {
+class LEVELDB_EXPORT FilterPolicy {
  public:
   virtual ~FilterPolicy();
 
@@ -63,8 +64,7 @@ class FilterPolicy {
 // ignores trailing spaces, it would be incorrect to use a
 // FilterPolicy (like NewBloomFilterPolicy) that does not ignore
 // trailing spaces in keys.
-extern const FilterPolicy* NewBloomFilterPolicy(int bits_per_key);
-
+LEVELDB_EXPORT const FilterPolicy* NewBloomFilterPolicy(int bits_per_key);
 }
 
 #endif  // STORAGE_LEVELDB_INCLUDE_FILTER_POLICY_H_

include/leveldb/iterator.h

@@ -15,12 +15,13 @@
 #ifndef STORAGE_LEVELDB_INCLUDE_ITERATOR_H_
 #define STORAGE_LEVELDB_INCLUDE_ITERATOR_H_
 
+#include "leveldb/export.h"
 #include "leveldb/slice.h"
 #include "leveldb/status.h"
 
 namespace leveldb {
 
-class Iterator {
+class LEVELDB_EXPORT Iterator {
  public:
   Iterator();
   virtual ~Iterator();
@@ -90,10 +91,10 @@ class Iterator {
 };
 
 // Return an empty iterator (yields nothing).
-extern Iterator* NewEmptyIterator();
+LEVELDB_EXPORT Iterator* NewEmptyIterator();
 
 // Return an empty iterator with the specified status.
-extern Iterator* NewErrorIterator(const Status& status);
+LEVELDB_EXPORT Iterator* NewErrorIterator(const Status& status);
 
 }  // namespace leveldb
 

include/leveldb/options.h

@@ -6,6 +6,7 @@
 #define STORAGE_LEVELDB_INCLUDE_OPTIONS_H_
 
 #include <stddef.h>
+#include "leveldb/export.h"
 
 namespace leveldb {
 
@@ -28,7 +29,7 @@ enum CompressionType {
 };
 
 // Options to control the behavior of a database (passed to DB::Open)
-struct Options {
+struct LEVELDB_EXPORT Options {
   // -------------------
   // Parameters that affect behavior
 
@@ -158,7 +159,7 @@ struct Options {
 };
 
 // Options that control read operations
-struct ReadOptions {
+struct LEVELDB_EXPORT ReadOptions {
   // If true, all data read from underlying storage will be
   // verified against corresponding checksums.
   // Default: false
@@ -184,7 +185,7 @@ struct ReadOptions {
 };
 
 // Options that control write operations
-struct WriteOptions {
+struct LEVELDB_EXPORT WriteOptions {
   // If true, the write will be flushed from the operating system
   // buffer cache (by calling WritableFile::Sync()) before the write
   // is considered complete.  If this flag is true, writes will be

include/leveldb/slice.h

@@ -19,10 +19,11 @@
 #include <stddef.h>
 #include <string.h>
 #include <string>
+#include "leveldb/export.h"
 
 namespace leveldb {
 
-class Slice {
+class LEVELDB_EXPORT Slice {
  public:
   // Create an empty slice.
   Slice() : data_(""), size_(0) { }

include/leveldb/status.h

@@ -14,11 +14,12 @@
 #define STORAGE_LEVELDB_INCLUDE_STATUS_H_
 
 #include <string>
+#include "leveldb/export.h"
 #include "leveldb/slice.h"
 
 namespace leveldb {
 
-class Status {
+class LEVELDB_EXPORT Status {
  public:
   // Create a success status.
   Status() : state_(NULL) { }

include/leveldb/table.h

@@ -6,6 +6,7 @@
 #define STORAGE_LEVELDB_INCLUDE_TABLE_H_
 
 #include <stdint.h>
+#include "leveldb/export.h"
 #include "leveldb/iterator.h"
 
 namespace leveldb {
@@ -21,7 +22,7 @@ class TableCache;
 // A Table is a sorted map from strings to strings.  Tables are
 // immutable and persistent.  A Table may be safely accessed from
 // multiple threads without external synchronization.
-class Table {
+class LEVELDB_EXPORT Table {
  public:
   // Attempt to open the table that is stored in bytes [0..file_size)
   // of "file", and read the metadata entries necessary to allow

include/leveldb/table_builder.h

@@ -14,6 +14,7 @@
 #define STORAGE_LEVELDB_INCLUDE_TABLE_BUILDER_H_
 
 #include <stdint.h>
+#include "leveldb/export.h"
 #include "leveldb/options.h"
 #include "leveldb/status.h"
 
@@ -23,7 +24,7 @@ class BlockBuilder;
 class BlockHandle;
 class WritableFile;
 
-class TableBuilder {
+class LEVELDB_EXPORT TableBuilder {
  public:
   // Create a builder that will store the contents of the table it is
   // building in *file.  Does not close the file.  It is up to the

include/leveldb/write_batch.h

@@ -22,13 +22,14 @@
 #define STORAGE_LEVELDB_INCLUDE_WRITE_BATCH_H_
 
 #include <string>
+#include "leveldb/export.h"
 #include "leveldb/status.h"
 
 namespace leveldb {
 
 class Slice;
 
-class WriteBatch {
+class LEVELDB_EXPORT WriteBatch {
  public:
   WriteBatch();
   ~WriteBatch();