improving the C wrapper

Summary:
- rocksdb_property_int (so that we don't have to parse strings)
- and rocksdb_set_options (to allow controlling options via strings)
- a few other missing options exposed
- a documentation comment fix
Closes https://github.com/facebook/rocksdb/pull/1793

Differential Revision: D4456569

Pulled By: yiwu-arbug

fbshipit-source-id: 9f1fac1

db/c.cc

@@ -901,6 +901,17 @@ char* rocksdb_property_value(
   }
 }
 
+int rocksdb_property_int(
+    rocksdb_t* db,
+    const char* propname,
+    uint64_t *out_val) {
+  if (db->rep->GetIntProperty(Slice(propname), out_val)) {
+    return 0;
+  } else {
+    return -1;
+  }
+}
+
 char* rocksdb_property_value_cf(
     rocksdb_t* db,
     rocksdb_column_family_handle_t* column_family,
@@ -1487,6 +1498,14 @@ void rocksdb_options_set_cuckoo_table_factory(
   }
 }
 
+void rocksdb_set_options(
+    rocksdb_t* db, int count, const char* const keys[], const char* const values[], char** errptr) {
+        std::unordered_map<std::string, std::string> options_map;
+        for (int i=0; i<count; i++)
+            options_map[keys[i]] = values[i];
+        SaveError(errptr,
+            db->rep->SetOptions(options_map));
+    }
 
 rocksdb_options_t* rocksdb_options_create() {
   return new rocksdb_options_t;
@@ -1871,6 +1890,14 @@ void rocksdb_options_set_hard_rate_limit(rocksdb_options_t* opt, double v) {
   opt->rep.hard_rate_limit = v;
 }
 
+void rocksdb_options_set_soft_pending_compaction_bytes_limit(rocksdb_options_t* opt, size_t v) {
+  opt->rep.soft_pending_compaction_bytes_limit = v;
+}
+
+void rocksdb_options_set_hard_pending_compaction_bytes_limit(rocksdb_options_t* opt, size_t v) {
+  opt->rep.hard_pending_compaction_bytes_limit = v;
+}
+
 void rocksdb_options_set_rate_limit_delay_max_milliseconds(
     rocksdb_options_t* opt, unsigned int v) {
   opt->rep.rate_limit_delay_max_milliseconds = v;
@@ -1900,6 +1927,10 @@ void rocksdb_options_set_disable_auto_compactions(rocksdb_options_t* opt, int di
   opt->rep.disable_auto_compactions = disable;
 }
 
+void rocksdb_options_set_optimize_filters_for_hits(rocksdb_options_t* opt, int v) {
+  opt->rep.optimize_filters_for_hits = v;
+}
+
 void rocksdb_options_set_delete_obsolete_files_period_micros(
     rocksdb_options_t* opt, uint64_t v) {
   opt->rep.delete_obsolete_files_period_micros = v;

include/rocksdb/c.h

@@ -289,6 +289,10 @@ extern ROCKSDB_LIBRARY_API void rocksdb_release_snapshot(
    Else returns a pointer to a malloc()-ed null-terminated value. */
 extern ROCKSDB_LIBRARY_API char* rocksdb_property_value(rocksdb_t* db,
                                                         const char* propname);
+/* returns 0 on success, -1 otherwise */
+int rocksdb_property_int(
+    rocksdb_t* db,
+    const char* propname, uint64_t *out_val);
 
 extern ROCKSDB_LIBRARY_API char* rocksdb_property_value_cf(
     rocksdb_t* db, rocksdb_column_family_handle_t* column_family,
@@ -525,6 +529,8 @@ extern ROCKSDB_LIBRARY_API void rocksdb_options_set_cuckoo_table_factory(
     rocksdb_options_t* opt, rocksdb_cuckoo_table_options_t* table_options);
 
 /* Options */
+extern ROCKSDB_LIBRARY_API void rocksdb_set_options(
+    rocksdb_t* db, int count, const char* const keys[], const char* const values[], char** errptr);
 
 extern ROCKSDB_LIBRARY_API rocksdb_options_t* rocksdb_options_create();
 extern ROCKSDB_LIBRARY_API void rocksdb_options_destroy(rocksdb_options_t*);
@@ -634,6 +640,10 @@ extern ROCKSDB_LIBRARY_API void rocksdb_options_set_soft_rate_limit(
     rocksdb_options_t*, double);
 extern ROCKSDB_LIBRARY_API void rocksdb_options_set_hard_rate_limit(
     rocksdb_options_t*, double);
+extern ROCKSDB_LIBRARY_API void rocksdb_options_set_soft_pending_compaction_bytes_limit(
+    rocksdb_options_t* opt, size_t v);
+extern ROCKSDB_LIBRARY_API void rocksdb_options_set_hard_pending_compaction_bytes_limit(
+    rocksdb_options_t* opt, size_t v);
 extern ROCKSDB_LIBRARY_API void
 rocksdb_options_set_rate_limit_delay_max_milliseconds(rocksdb_options_t*,
                                                       unsigned int);
@@ -699,6 +709,8 @@ extern ROCKSDB_LIBRARY_API void rocksdb_options_set_disable_data_sync(
     rocksdb_options_t*, int);
 extern ROCKSDB_LIBRARY_API void rocksdb_options_set_disable_auto_compactions(
     rocksdb_options_t*, int);
+extern ROCKSDB_LIBRARY_API void rocksdb_options_set_optimize_filters_for_hits(
+    rocksdb_options_t*, int);
 extern ROCKSDB_LIBRARY_API void
 rocksdb_options_set_delete_obsolete_files_period_micros(rocksdb_options_t*,
                                                         uint64_t);

include/rocksdb/db.h

@@ -464,7 +464,7 @@ class DB {
     static const std::string kNumDeletesImmMemTables;
 
     //  "rocksdb.estimate-num-keys" - returns estimated number of total keys in
-    //      the active and unflushed immutable memtables.
+    //      the active and unflushed immutable memtables and storage.
     static const std::string kEstimateNumKeys;
 
     //  "rocksdb.estimate-table-readers-mem" - returns estimated memory used for