Add rocksdb::ToString() to address cases where std::to_string is not available.

Summary:
In some environment such as android, the c++ library does not have
std::to_string.  This path adds rocksdb::ToString(), which wraps std::to_string
when std::to_string is not available, and implements std::to_string
in the other case.

Test Plan:
make dbg -j32
./db_test
make clean
make dbg OPT=-DOS_ANDROID -j32
./db_test

Reviewers: ljin, sdong, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D29181

db/column_family_test.cc

@@ -218,7 +218,7 @@ class ColumnFamilyTest {
 
   int NumTableFilesAtLevel(int level, int cf) {
     return GetProperty(cf,
-                       "rocksdb.num-files-at-level" + std::to_string(level));
+                       "rocksdb.num-files-at-level" + ToString(level));
   }
 
   // Return spread of files per level
@@ -387,7 +387,7 @@ TEST(ColumnFamilyTest, DropTest) {
     Open({"default"});
     CreateColumnFamiliesAndReopen({"pikachu"});
     for (int i = 0; i < 100; ++i) {
-      ASSERT_OK(Put(1, std::to_string(i), "bar" + std::to_string(i)));
+      ASSERT_OK(Put(1, ToString(i), "bar" + ToString(i)));
     }
     ASSERT_OK(Flush(1));
 
@@ -774,14 +774,14 @@ TEST(ColumnFamilyTest, DifferentCompactionStyles) {
   for (int i = 0; i < one.level0_file_num_compaction_trigger - 1; ++i) {
     PutRandomData(1, 11, 10000);
     WaitForFlush(1);
-    ASSERT_EQ(std::to_string(i + 1), FilesPerLevel(1));
+    ASSERT_EQ(ToString(i + 1), FilesPerLevel(1));
   }
 
   // SETUP column family "two" -- level style with 4 levels
   for (int i = 0; i < two.level0_file_num_compaction_trigger - 1; ++i) {
     PutRandomData(2, 15, 10000);
     WaitForFlush(2);
-    ASSERT_EQ(std::to_string(i + 1), FilesPerLevel(2));
+    ASSERT_EQ(ToString(i + 1), FilesPerLevel(2));
   }
 
   // TRIGGER compaction "one"

db/compaction_job_test.cc

@@ -60,8 +60,8 @@ class CompactionJobTest {
       SequenceNumber smallest_seqno = 0, largest_seqno = 0;
       InternalKey smallest, largest;
       for (int k = 0; k < kKeysPerFile; ++k) {
-        auto key = std::to_string(i * (kKeysPerFile / 2) + k);
+        auto key = ToString(i * (kKeysPerFile / 2) + k);
-        auto value = std::to_string(i * kKeysPerFile + k);
+        auto value = ToString(i * kKeysPerFile + k);
         InternalKey internal_key(key, ++sequence_number, kTypeValue);
         if (k == 0) {
           smallest = internal_key;

db/compaction_picker.cc

@@ -19,6 +19,7 @@
 #include "db/filename.h"
 #include "util/log_buffer.h"
 #include "util/statistics.h"
+#include "util/string_util.h"
 
 namespace rocksdb {
 
@@ -262,7 +263,7 @@ Status CompactionPicker::GetCompactionInputsFromFileNumbers(
         "Cannot find matched SST files for the following file numbers:");
     for (auto fn : *input_set) {
       message += " ";
-      message += std::to_string(fn);
+      message += ToString(fn);
     }
     return Status::InvalidArgument(message);
   }
@@ -616,7 +617,7 @@ Status CompactionPicker::SanitizeCompactionInputFiles(
     return Status::InvalidArgument(
         "Output level for column family " + cf_meta.name +
         " must between [0, " +
-        std::to_string(cf_meta.levels[cf_meta.levels.size() - 1].level) +
+        ToString(cf_meta.levels[cf_meta.levels.size() - 1].level) +
         "].");
   }
 
@@ -624,7 +625,7 @@ Status CompactionPicker::SanitizeCompactionInputFiles(
     return Status::InvalidArgument(
         "Exceed the maximum output level defined by "
         "the current compaction algorithm --- " +
-            std::to_string(MaxOutputLevel()));
+            ToString(MaxOutputLevel()));
   }
 
   if (output_level < 0) {

db/compaction_picker_test.cc

@@ -192,8 +192,8 @@ TEST(CompactionPickerTest, NeedsCompactionLevel) {
       // start a brand new version in each test.
       NewVersionStorage(kLevels, kCompactionStyleLevel);
       for (int i = 0; i < file_count; ++i) {
-        Add(level, i, std::to_string((i + 100) * 1000).c_str(),
+        Add(level, i, ToString((i + 100) * 1000).c_str(),
-            std::to_string((i + 100) * 1000 + 999).c_str(),
+            ToString((i + 100) * 1000 + 999).c_str(),
             file_size, 0, i * 100, i * 100 + 99);
       }
       UpdateVersionStorageInfo();
@@ -217,8 +217,8 @@ TEST(CompactionPickerTest, NeedsCompactionUniversal) {
   // verify the trigger given different number of L0 files.
   for (int i = 1;
        i <= mutable_cf_options_.level0_file_num_compaction_trigger * 2; ++i) {
-    Add(0, i, std::to_string((i + 100) * 1000).c_str(),
+    Add(0, i, ToString((i + 100) * 1000).c_str(),
-        std::to_string((i + 100) * 1000 + 999).c_str(), 1000000, 0, i * 100,
+        ToString((i + 100) * 1000 + 999).c_str(), 1000000, 0, i * 100,
         i * 100 + 99);
     ASSERT_EQ(level_compaction_picker.NeedsCompaction(vstorage_.get()),
               vstorage_->CompactionScore(0) >= 1);
@@ -243,8 +243,8 @@ TEST(CompactionPickerTest, NeedsCompactionFIFO) {
   // size of L0 files.
   uint64_t current_size = 0;
   for (int i = 1; i <= kFileCount; ++i) {
-    Add(0, i, std::to_string((i + 100) * 1000).c_str(),
+    Add(0, i, ToString((i + 100) * 1000).c_str(),
-        std::to_string((i + 100) * 1000 + 999).c_str(),
+        ToString((i + 100) * 1000 + 999).c_str(),
         kFileSize, 0, i * 100, i * 100 + 99);
     current_size += kFileSize;
     ASSERT_EQ(level_compaction_picker.NeedsCompaction(vstorage_.get()),

db/comparator_db_test.cc

@@ -377,7 +377,7 @@ TEST(ComparatorDBTest, DoubleComparator) {
       for (uint32_t j = 0; j < divide_order; j++) {
         to_divide *= 10.0;
       }
-      source_strings.push_back(std::to_string(r / to_divide));
+      source_strings.push_back(ToString(r / to_divide));
     }
 
     DoRandomIteraratorTest(GetDB(), source_strings, &rnd, 200, 1000, 66);

db/db_bench.cc

@@ -1350,7 +1350,7 @@ class Benchmark {
   }
 
   std::string GetDbNameForMultiple(std::string base_name, size_t id) {
-    return base_name + std::to_string(id);
+    return base_name + ToString(id);
   }
 
   std::string ColumnFamilyName(int i) {

db/db_impl.cc

@@ -75,6 +75,7 @@
 #include "util/iostats_context_imp.h"
 #include "util/stop_watch.h"
 #include "util/sync_point.h"
+#include "util/string_util.h"
 #include "util/thread_status_impl.h"
 
 namespace rocksdb {
@@ -3121,7 +3122,7 @@ bool DBImpl::GetProperty(ColumnFamilyHandle* column_family,
     bool ret_value = GetIntPropertyInternal(column_family, property_type,
                                             need_out_of_mutex, &int_value);
     if (ret_value) {
-      *value = std::to_string(int_value);
+      *value = ToString(int_value);
     }
     return ret_value;
   } else {
@@ -3378,8 +3379,8 @@ Status DBImpl::CheckConsistency() {
     } else if (fsize != md.size) {
       corruption_messages += "Sst file size mismatch: " + file_path +
                              ". Size recorded in manifest " +
-                             std::to_string(md.size) + ", actual size " +
+                             ToString(md.size) + ", actual size " +
-                             std::to_string(fsize) + "\n";
+                             ToString(fsize) + "\n";
     }
   }
   if (corruption_messages.size() == 0) {

db/db_iter_test.cc

@@ -366,7 +366,7 @@ TEST(DBIteratorTest, DBIteratorUseSkip) {
       internal_iter->AddMerge("b", "merge_1");
       internal_iter->AddMerge("a", "merge_2");
       for (size_t k = 0; k < 200; ++k) {
-        internal_iter->AddPut("c", std::to_string(k));
+        internal_iter->AddPut("c", ToString(k));
       }
       internal_iter->Finish();
 
@@ -379,7 +379,7 @@ TEST(DBIteratorTest, DBIteratorUseSkip) {
       ASSERT_TRUE(db_iter->Valid());
 
       ASSERT_EQ(db_iter->key().ToString(), "c");
-      ASSERT_EQ(db_iter->value().ToString(), std::to_string(i));
+      ASSERT_EQ(db_iter->value().ToString(), ToString(i));
       db_iter->Prev();
       ASSERT_TRUE(db_iter->Valid());
 
@@ -513,11 +513,11 @@ TEST(DBIteratorTest, DBIteratorUseSkip) {
       internal_iter->AddMerge("b", "merge_1");
       internal_iter->AddMerge("a", "merge_2");
       for (size_t k = 0; k < 200; ++k) {
-        internal_iter->AddPut("d", std::to_string(k));
+        internal_iter->AddPut("d", ToString(k));
       }
 
       for (size_t k = 0; k < 200; ++k) {
-        internal_iter->AddPut("c", std::to_string(k));
+        internal_iter->AddPut("c", ToString(k));
       }
       internal_iter->Finish();
 
@@ -529,7 +529,7 @@ TEST(DBIteratorTest, DBIteratorUseSkip) {
       ASSERT_TRUE(db_iter->Valid());
 
       ASSERT_EQ(db_iter->key().ToString(), "d");
-      ASSERT_EQ(db_iter->value().ToString(), std::to_string(i));
+      ASSERT_EQ(db_iter->value().ToString(), ToString(i));
       db_iter->Prev();
       ASSERT_TRUE(db_iter->Valid());
 
@@ -552,7 +552,7 @@ TEST(DBIteratorTest, DBIteratorUseSkip) {
       internal_iter->AddMerge("b", "b");
       internal_iter->AddMerge("a", "a");
       for (size_t k = 0; k < 200; ++k) {
-        internal_iter->AddMerge("c", std::to_string(k));
+        internal_iter->AddMerge("c", ToString(k));
       }
       internal_iter->Finish();
 
@@ -566,7 +566,7 @@ TEST(DBIteratorTest, DBIteratorUseSkip) {
       ASSERT_EQ(db_iter->key().ToString(), "c");
       std::string merge_result = "0";
       for (size_t j = 1; j <= i; ++j) {
-        merge_result += "," + std::to_string(j);
+        merge_result += "," + ToString(j);
       }
       ASSERT_EQ(db_iter->value().ToString(), merge_result);
 

db/db_test.cc

@@ -50,6 +50,7 @@
 #include "util/sync_point.h"
 #include "util/testutil.h"
 #include "util/mock_env.h"
+#include "util/string_util.h"
 #include "util/thread_status_impl.h"
 
 namespace rocksdb {
@@ -1494,7 +1495,7 @@ TEST(DBTest, GetPropertiesOfAllTablesTest) {
   // Create 4 tables
   for (int table = 0; table < 4; ++table) {
     for (int i = 0; i < 10 + table; ++i) {
-      db_->Put(WriteOptions(), std::to_string(table * 100 + i), "val");
+      db_->Put(WriteOptions(), ToString(table * 100 + i), "val");
     }
     db_->Flush(FlushOptions());
   }
@@ -1508,7 +1509,7 @@ TEST(DBTest, GetPropertiesOfAllTablesTest) {
   // fetch key from 1st and 2nd table, which will internally place that table to
   // the table cache.
   for (int i = 0; i < 2; ++i) {
-    Get(std::to_string(i * 100 + 0));
+    Get(ToString(i * 100 + 0));
   }
 
   VerifyTableProperties(db_, 10 + 11 + 12 + 13);
@@ -1518,7 +1519,7 @@ TEST(DBTest, GetPropertiesOfAllTablesTest) {
   // fetch key from 1st and 2nd table, which will internally place that table to
   // the table cache.
   for (int i = 0; i < 4; ++i) {
-    Get(std::to_string(i * 100 + 0));
+    Get(ToString(i * 100 + 0));
   }
   VerifyTableProperties(db_, 10 + 11 + 12 + 13);
 }
@@ -4747,7 +4748,7 @@ TEST(DBTest, CompactionFilterDeletesAll) {
   // put some data
   for (int table = 0; table < 4; ++table) {
     for (int i = 0; i < 10 + table; ++i) {
-      Put(std::to_string(table * 100 + i), "val");
+      Put(ToString(table * 100 + i), "val");
     }
     Flush();
   }
@@ -6994,7 +6995,7 @@ TEST(DBTest, TransactionLogIteratorCorruptedLog) {
     Options options = OptionsForLogIterTest();
     DestroyAndReopen(options);
     for (int i = 0; i < 1024; i++) {
-      Put("key"+std::to_string(i), DummyString(10));
+      Put("key"+ToString(i), DummyString(10));
     }
     dbfull()->Flush(FlushOptions());
     // Corrupt this log to create a gap
@@ -7062,20 +7063,20 @@ TEST(DBTest, TransactionLogIteratorBlobs) {
   struct Handler : public WriteBatch::Handler {
     std::string seen;
     virtual Status PutCF(uint32_t cf, const Slice& key, const Slice& value) {
-      seen += "Put(" + std::to_string(cf) + ", " + key.ToString() + ", " +
+      seen += "Put(" + ToString(cf) + ", " + key.ToString() + ", " +
-              std::to_string(value.size()) + ")";
+              ToString(value.size()) + ")";
       return Status::OK();
     }
     virtual Status MergeCF(uint32_t cf, const Slice& key, const Slice& value) {
-      seen += "Merge(" + std::to_string(cf) + ", " + key.ToString() + ", " +
+      seen += "Merge(" + ToString(cf) + ", " + key.ToString() + ", " +
-              std::to_string(value.size()) + ")";
+              ToString(value.size()) + ")";
       return Status::OK();
     }
     virtual void LogData(const Slice& blob) {
       seen += "LogData(" + blob.ToString() + ")";
     }
     virtual Status DeleteCF(uint32_t cf, const Slice& key) {
-      seen += "Delete(" + std::to_string(cf) + ", " + key.ToString() + ")";
+      seen += "Delete(" + ToString(cf) + ", " + key.ToString() + ")";
       return Status::OK();
     }
   } handler;
@@ -7203,7 +7204,7 @@ TEST(DBTest, MultiThreaded) {
   do {
     std::vector<std::string> cfs;
     for (int i = 1; i < kColumnFamilies; ++i) {
-      cfs.push_back(std::to_string(i));
+      cfs.push_back(ToString(i));
     }
     CreateAndReopenWithCF(cfs, CurrentOptions());
     // Initialize state
@@ -7256,7 +7257,7 @@ static void GCThreadBody(void* arg) {
   WriteOptions wo;
 
   for (int i = 0; i < kGCNumKeys; ++i) {
-    std::string kv(std::to_string(i + id * kGCNumKeys));
+    std::string kv(ToString(i + id * kGCNumKeys));
     ASSERT_OK(db->Put(wo, kv, kv));
   }
   t->done = true;
@@ -7292,7 +7293,7 @@ TEST(DBTest, GroupCommitTest) {
 
     std::vector<std::string> expected_db;
     for (int i = 0; i < kGCNumThreads * kGCNumKeys; ++i) {
-      expected_db.push_back(std::to_string(i));
+      expected_db.push_back(ToString(i));
     }
     sort(expected_db.begin(), expected_db.end());
 
@@ -8176,7 +8177,7 @@ TEST(DBTest, FIFOCompactionTest) {
     Random rnd(301);
     for (int i = 0; i < 6; ++i) {
       for (int j = 0; j < 100; ++j) {
-        ASSERT_OK(Put(std::to_string(i * 100 + j), RandomString(&rnd, 1024)));
+        ASSERT_OK(Put(ToString(i * 100 + j), RandomString(&rnd, 1024)));
       }
       // flush should happen here
     }
@@ -8189,7 +8190,7 @@ TEST(DBTest, FIFOCompactionTest) {
     ASSERT_EQ(NumTableFilesAtLevel(0), 5);
     for (int i = 0; i < 50; ++i) {
       // these keys should be deleted in previous compaction
-      ASSERT_EQ("NOT_FOUND", Get(std::to_string(i)));
+      ASSERT_EQ("NOT_FOUND", Get(ToString(i)));
     }
   }
 }
@@ -8517,7 +8518,7 @@ TEST(DBTest, CompactFilesOnLevelCompaction) {
 
   Random rnd(301);
   for (int key = 64 * kEntriesPerBuffer; key >= 0; --key) {
-    ASSERT_OK(Put(1, std::to_string(key), RandomString(&rnd, kTestValueSize)));
+    ASSERT_OK(Put(1, ToString(key), RandomString(&rnd, kTestValueSize)));
   }
   dbfull()->TEST_WaitForFlushMemTable(handles_[1]);
   dbfull()->TEST_WaitForCompact();
@@ -8549,7 +8550,7 @@ TEST(DBTest, CompactFilesOnLevelCompaction) {
 
   // make sure all key-values are still there.
   for (int key = 64 * kEntriesPerBuffer; key >= 0; --key) {
-    ASSERT_NE(Get(1, std::to_string(key)), "NOT_FOUND");
+    ASSERT_NE(Get(1, ToString(key)), "NOT_FOUND");
   }
 }
 
@@ -8571,7 +8572,7 @@ TEST(DBTest, CompactFilesOnUniversalCompaction) {
   ASSERT_EQ(options.compaction_style, kCompactionStyleUniversal);
   Random rnd(301);
   for (int key = 1024 * kEntriesPerBuffer; key >= 0; --key) {
-    ASSERT_OK(Put(1, std::to_string(key), RandomString(&rnd, kTestValueSize)));
+    ASSERT_OK(Put(1, ToString(key), RandomString(&rnd, kTestValueSize)));
   }
   dbfull()->TEST_WaitForFlushMemTable(handles_[1]);
   dbfull()->TEST_WaitForCompact();
@@ -9112,7 +9113,7 @@ TEST(DBTest, DynamicCompactionOptions) {
   // result in 2 32KB L1 files.
   ASSERT_OK(dbfull()->SetOptions({
     {"level0_file_num_compaction_trigger", "2"},
-    {"target_file_size_base", std::to_string(k32KB) }
+    {"target_file_size_base", ToString(k32KB) }
   }));
 
   gen_l0_kb(0, 64, 1);
@@ -9133,7 +9134,7 @@ TEST(DBTest, DynamicCompactionOptions) {
   // fill L1 and L2. L1 size should be around 256KB while L2 size should be
   // around 256KB x 4.
   ASSERT_OK(dbfull()->SetOptions({
-    {"max_bytes_for_level_base", std::to_string(k1MB) }
+    {"max_bytes_for_level_base", ToString(k1MB) }
   }));
 
   // writing 96 x 64KB => 6 * 1024KB
@@ -9155,7 +9156,7 @@ TEST(DBTest, DynamicCompactionOptions) {
   // reduces to 128KB from 256KB which was asserted previously. Same for L2.
   ASSERT_OK(dbfull()->SetOptions({
     {"max_bytes_for_level_multiplier", "2"},
-    {"max_bytes_for_level_base", std::to_string(k128KB) }
+    {"max_bytes_for_level_base", ToString(k128KB) }
   }));
 
   // writing 20 x 64KB = 10 x 128KB
@@ -9255,7 +9256,7 @@ TEST(DBTest, DynamicCompactionOptions) {
   // L1 - L3. Then thrink max_bytes_for_level_base and disable auto compaction
   // at the same time, we should see some level with score greater than 2.
   ASSERT_OK(dbfull()->SetOptions({
-    {"max_bytes_for_level_base", std::to_string(k1MB) }
+    {"max_bytes_for_level_base", ToString(k1MB) }
   }));
   // writing 40 x 64KB = 10 x 256KB
   // (L1 + L2 + L3) = (1 + 2 + 4) * 256KB

db/deletefile_test.cc

@@ -79,7 +79,7 @@ class DeleteFileTest {
     options.sync = false;
     ReadOptions roptions;
     for (int i = startkey; i < (numkeys + startkey) ; i++) {
-      std::string temp = std::to_string(i);
+      std::string temp = ToString(i);
       Slice key(temp);
       Slice value(temp);
       ASSERT_OK(db_->Put(options, key, value));

db/flush_job_test.cc

@@ -97,8 +97,8 @@ TEST(FlushJobTest, NonEmpty) {
   new_mem->Ref();
   std::map<std::string, std::string> inserted_keys;
   for (int i = 1; i < 10000; ++i) {
-    std::string key(std::to_string(i));
+    std::string key(ToString(i));
-    std::string value("value" + std::to_string(i));
+    std::string value("value" + ToString(i));
     new_mem->Add(SequenceNumber(i), kTypeValue, key, value);
     InternalKey internal_key(key, SequenceNumber(i), kTypeValue);
     inserted_keys.insert({internal_key.Encode().ToString(), value});

db/internal_stats.cc

@@ -16,6 +16,7 @@
 #include <vector>
 #include "db/column_family.h"
 #include "db/db_impl.h"
+#include "util/string_util.h"
 
 namespace rocksdb {
 
@@ -433,7 +434,7 @@ void InternalStats::DumpCFStats(std::string* value) {
       double w_amp = (comp_stats_[level].bytes_readn == 0) ? 0.0
           : comp_stats_[level].bytes_written /
             static_cast<double>(comp_stats_[level].bytes_readn);
-      PrintLevelStats(buf, sizeof(buf), "L" + std::to_string(level), files,
+      PrintLevelStats(buf, sizeof(buf), "L" + ToString(level), files,
                       files_being_compacted[level],
                       vstorage->NumLevelBytes(level), compaction_score[level],
                       rw_amp, w_amp, stall_us, stalls, comp_stats_[level]);

db/listener_test.cc

@@ -258,10 +258,10 @@ TEST(EventListenerTest, MultiDBMultiListeners) {
   std::vector<std::vector<ColumnFamilyHandle *>> vec_handles;
 
   for (int d = 0; d < kNumDBs; ++d) {
-    ASSERT_OK(DestroyDB(dbname_ + std::to_string(d), options));
+    ASSERT_OK(DestroyDB(dbname_ + ToString(d), options));
     DB* db;
     std::vector<ColumnFamilyHandle*> handles;
-    ASSERT_OK(DB::Open(options, dbname_ + std::to_string(d), &db));
+    ASSERT_OK(DB::Open(options, dbname_ + ToString(d), &db));
     for (size_t c = 0; c < cf_names.size(); ++c) {
       ColumnFamilyHandle* handle;
       db->CreateColumnFamily(cf_opts, cf_names[c], &handle);
@@ -331,7 +331,7 @@ TEST(EventListenerTest, DisableBGCompaction) {
   db_->GetColumnFamilyMetaData(handles_[1], &cf_meta);
   // keep writing until writes are forced to stop.
   for (int i = 0; static_cast<int>(cf_meta.file_count) < kStopTrigger; ++i) {
-    Put(1, std::to_string(i), std::string(100000, 'x'), wopts);
+    Put(1, ToString(i), std::string(100000, 'x'), wopts);
     db_->GetColumnFamilyMetaData(handles_[1], &cf_meta);
   }
   ASSERT_GE(listener->slowdown_count, kStopTrigger - kSlowdownTrigger);

db/perf_context_test.cc

@@ -14,6 +14,7 @@
 #include "util/histogram.h"
 #include "util/stop_watch.h"
 #include "util/testharness.h"
+#include "util/string_util.h"
 
 
 bool FLAGS_random_key = false;
@@ -66,21 +67,21 @@ TEST(PerfContextTest, SeekIntoDeletion) {
   ReadOptions read_options;
 
   for (int i = 0; i < FLAGS_total_keys; ++i) {
-    std::string key = "k" + std::to_string(i);
+    std::string key = "k" + ToString(i);
-    std::string value = "v" + std::to_string(i);
+    std::string value = "v" + ToString(i);
 
     db->Put(write_options, key, value);
   }
 
   for (int i = 0; i < FLAGS_total_keys -1 ; ++i) {
-    std::string key = "k" + std::to_string(i);
+    std::string key = "k" + ToString(i);
     db->Delete(write_options, key);
   }
 
   HistogramImpl hist_get;
   HistogramImpl hist_get_time;
   for (int i = 0; i < FLAGS_total_keys - 1; ++i) {
-    std::string key = "k" + std::to_string(i);
+    std::string key = "k" + ToString(i);
     std::string value;
 
     perf_context.Reset();
@@ -118,7 +119,7 @@ TEST(PerfContextTest, SeekIntoDeletion) {
   HistogramImpl hist_seek;
   for (int i = 0; i < FLAGS_total_keys; ++i) {
     std::unique_ptr<Iterator> iter(db->NewIterator(read_options));
-    std::string key = "k" + std::to_string(i);
+    std::string key = "k" + ToString(i);
 
     perf_context.Reset();
     StopWatchNano timer(Env::Default(), true);
@@ -231,8 +232,8 @@ void ProfileQueries(bool enabled_time = false) {
       db->Flush(fo);
       continue;
     }
-    std::string key = "k" + std::to_string(i);
+    std::string key = "k" + ToString(i);
-    std::string value = "v" + std::to_string(i);
+    std::string value = "v" + ToString(i);
 
     std::vector<std::string> values;
 
@@ -245,8 +246,8 @@ void ProfileQueries(bool enabled_time = false) {
   }
 
   for (const int i : keys) {
-    std::string key = "k" + std::to_string(i);
+    std::string key = "k" + ToString(i);
-    std::string value = "v" + std::to_string(i);
+    std::string value = "v" + ToString(i);
 
     std::vector<Slice> multiget_keys = {Slice(key)};
     std::vector<std::string> values;
@@ -335,8 +336,8 @@ void ProfileQueries(bool enabled_time = false) {
   hist_mget_num_memtable_checked.Clear();
 
   for (const int i : keys) {
-    std::string key = "k" + std::to_string(i);
+    std::string key = "k" + ToString(i);
-    std::string value = "v" + std::to_string(i);
+    std::string value = "v" + ToString(i);
 
     std::vector<Slice> multiget_keys = {Slice(key)};
     std::vector<std::string> values;
@@ -451,8 +452,8 @@ TEST(PerfContextTest, SeekKeyComparison) {
   SetPerfLevel(kEnableTime);
   StopWatchNano timer(Env::Default());
   for (const int i : keys) {
-    std::string key = "k" + std::to_string(i);
+    std::string key = "k" + ToString(i);
-    std::string value = "v" + std::to_string(i);
+    std::string value = "v" + ToString(i);
 
     perf_context.Reset();
     timer.Start();
@@ -471,8 +472,8 @@ TEST(PerfContextTest, SeekKeyComparison) {
   HistogramImpl hist_next;
 
   for (int i = 0; i < FLAGS_total_keys; ++i) {
-    std::string key = "k" + std::to_string(i);
+    std::string key = "k" + ToString(i);
-    std::string value = "v" + std::to_string(i);
+    std::string value = "v" + ToString(i);
 
     std::unique_ptr<Iterator> iter(db->NewIterator(read_options));
     perf_context.Reset();

db/plain_table_db_test.cc

@@ -628,7 +628,7 @@ TEST(PlainTableDBTest, IteratorLargeKeys) {
   };
 
   for (size_t i = 0; i < 7; i++) {
-    ASSERT_OK(Put(key_list[i], std::to_string(i)));
+    ASSERT_OK(Put(key_list[i], ToString(i)));
   }
 
   dbfull()->TEST_FlushMemTable();
@@ -639,7 +639,7 @@ TEST(PlainTableDBTest, IteratorLargeKeys) {
   for (size_t i = 0; i < 7; i++) {
     ASSERT_TRUE(iter->Valid());
     ASSERT_EQ(key_list[i], iter->key().ToString());
-    ASSERT_EQ(std::to_string(i), iter->value().ToString());
+    ASSERT_EQ(ToString(i), iter->value().ToString());
     iter->Next();
   }
 
@@ -676,7 +676,7 @@ TEST(PlainTableDBTest, IteratorLargeKeysWithPrefix) {
       MakeLongKeyWithPrefix(26, '6')};
 
   for (size_t i = 0; i < 7; i++) {
-    ASSERT_OK(Put(key_list[i], std::to_string(i)));
+    ASSERT_OK(Put(key_list[i], ToString(i)));
   }
 
   dbfull()->TEST_FlushMemTable();
@@ -687,7 +687,7 @@ TEST(PlainTableDBTest, IteratorLargeKeysWithPrefix) {
   for (size_t i = 0; i < 7; i++) {
     ASSERT_TRUE(iter->Valid());
     ASSERT_EQ(key_list[i], iter->key().ToString());
-    ASSERT_EQ(std::to_string(i), iter->value().ToString());
+    ASSERT_EQ(ToString(i), iter->value().ToString());
     iter->Next();
   }
 

db/prefix_test.cc

@@ -442,7 +442,7 @@ TEST(PrefixTest, DynamicPrefixIterator) {
     for (auto prefix : prefixes) {
       TestKey test_key(prefix, FLAGS_items_per_prefix / 2);
       Slice key = TestKeyToSlice(test_key);
-      std::string value = "v" + std::to_string(0);
+      std::string value = "v" + ToString(0);
 
       perf_context.Reset();
       StopWatchNano timer(Env::Default(), true);

db/table_properties_collector.cc

@@ -7,6 +7,7 @@
 
 #include "db/dbformat.h"
 #include "util/coding.h"
+#include "util/string_util.h"
 
 namespace rocksdb {
 
@@ -40,7 +41,7 @@ Status InternalKeyPropertiesCollector::Finish(
 UserCollectedProperties
 InternalKeyPropertiesCollector::GetReadableProperties() const {
   return {
-    { "kDeletedKeys", std::to_string(deleted_keys_) }
+    { "kDeletedKeys", ToString(deleted_keys_) }
   };
 }
 

db/version_builder_test.cc

@@ -135,8 +135,8 @@ TEST(VersionBuilderTest, EstimatedActiveKeys) {
   const uint32_t kDeletionsPerFile = 100;
   for (uint32_t i = 0; i < kNumFiles; ++i) {
     Add(static_cast<int>(i / kFilesPerLevel), i + 1,
-        std::to_string((i + 100) * 1000).c_str(),
+        ToString((i + 100) * 1000).c_str(),
-        std::to_string((i + 100) * 1000 + 999).c_str(),
+        ToString((i + 100) * 1000 + 999).c_str(),
         100U,  0, 100, 100,
         kEntriesPerFile, kDeletionsPerFile,
         (i < kTotalSamples));

db/wal_manager.cc

@@ -31,6 +31,7 @@
 #include "util/logging.h"
 #include "util/mutexlock.h"
 #include "util/sync_point.h"
+#include "util/string_util.h"
 
 namespace rocksdb {
 
@@ -355,9 +356,9 @@ Status WalManager::ReadFirstRecord(const WalFileType type,
                                    SequenceNumber* sequence) {
   if (type != kAliveLogFile && type != kArchivedLogFile) {
     Log(InfoLogLevel::ERROR_LEVEL, db_options_.info_log,
-        "[WalManger] Unknown file type %s", std::to_string(type).c_str());
+        "[WalManger] Unknown file type %s", ToString(type).c_str());
     return Status::NotSupported(
-        "File Type Not Known " + std::to_string(type));
+        "File Type Not Known " + ToString(type));
   }
   {
     MutexLock l(&read_first_record_cache_mutex_);

db/wal_manager_test.cc

@@ -73,7 +73,7 @@ class WalManagerTest {
     for (int i = 1; i <= num_logs; ++i) {
       RollTheLog(true);
       for (int k = 0; k < entries_per_log; ++k) {
-        Put(std::to_string(k), std::string(1024, 'a'));
+        Put(ToString(k), std::string(1024, 'a'));
       }
     }
   }

db/write_batch_test.cc

@@ -155,7 +155,7 @@ namespace {
       if (column_family_id == 0) {
         seen += "Put(" + key.ToString() + ", " + value.ToString() + ")";
       } else {
-        seen += "PutCF(" + std::to_string(column_family_id) + ", " +
+        seen += "PutCF(" + ToString(column_family_id) + ", " +
                 key.ToString() + ", " + value.ToString() + ")";
       }
       return Status::OK();
@@ -165,7 +165,7 @@ namespace {
       if (column_family_id == 0) {
         seen += "Merge(" + key.ToString() + ", " + value.ToString() + ")";
       } else {
-        seen += "MergeCF(" + std::to_string(column_family_id) + ", " +
+        seen += "MergeCF(" + ToString(column_family_id) + ", " +
                 key.ToString() + ", " + value.ToString() + ")";
       }
       return Status::OK();
@@ -177,7 +177,7 @@ namespace {
       if (column_family_id == 0) {
         seen += "Delete(" + key.ToString() + ")";
       } else {
-        seen += "DeleteCF(" + std::to_string(column_family_id) + ", " +
+        seen += "DeleteCF(" + ToString(column_family_id) + ", " +
                 key.ToString() + ")";
       }
       return Status::OK();

examples/compact_files_example.cc

@@ -156,14 +156,14 @@ int main() {
   // if background compaction is not working, write will stall
   // because of options.level0_stop_writes_trigger
   for (int i = 1000; i < 99999; ++i) {
-    db->Put(WriteOptions(), std::to_string(i),
+    db->Put(WriteOptions(), ToString(i),
                             std::string(500, 'a' + (i % 26)));
   }
 
   // verify the values are still there
   std::string value;
   for (int i = 1000; i < 99999; ++i) {
-    db->Get(ReadOptions(), std::to_string(i),
+    db->Get(ReadOptions(), ToString(i),
                            &value);
     assert(value == std::string(500, 'a' + (i % 26)));
   }

port/port.h

@@ -10,13 +10,13 @@
 #ifndef STORAGE_LEVELDB_PORT_PORT_H_
 #define STORAGE_LEVELDB_PORT_PORT_H_
 
-#include <string.h>
+#include <string>
 
 // Include the appropriate platform specific file below.  If you are
 // porting to a new platform, see "port_example.h" for documentation
 // of what the new port_<platform>.h file must provide.
 #if defined(ROCKSDB_PLATFORM_POSIX)
-#  include "port/port_posix.h"
+#include "port/port_posix.h"
 #endif
 
 #endif  // STORAGE_LEVELDB_PORT_PORT_H_

table/block_based_table_reader.cc

@@ -38,6 +38,7 @@
 #include "util/coding.h"
 #include "util/perf_context_imp.h"
 #include "util/stop_watch.h"
+#include "util/string_util.h"
 
 namespace rocksdb {
 
@@ -1264,7 +1265,7 @@ Status BlockBasedTable::CreateIndexReader(IndexReader** index_reader,
     }
     default: {
       std::string error_message =
-          "Unrecognized index type: " + std::to_string(rep_->index_type);
+          "Unrecognized index type: " + ToString(rep_->index_type);
       return Status::InvalidArgument(error_message.c_str());
     }
   }

table/cuckoo_table_builder.cc

@@ -21,6 +21,7 @@
 #include "table/meta_blocks.h"
 #include "util/autovector.h"
 #include "util/random.h"
+#include "util/string_util.h"
 
 namespace rocksdb {
 const std::string CuckooTablePropertyNames::kEmptyKey =
@@ -88,7 +89,7 @@ void CuckooTableBuilder::Add(const Slice& key, const Slice& value) {
   }
   if (ikey.type != kTypeDeletion && ikey.type != kTypeValue) {
     status_ = Status::NotSupported("Unsupported key type " +
-                                   std::to_string(ikey.type));
+                                   ToString(ikey.type));
     return;
   }
 

table/cuckoo_table_reader_test.cc

@@ -387,7 +387,7 @@ std::string GetFileName(uint64_t num) {
     FLAGS_file_dir = test::TmpDir();
   }
   return FLAGS_file_dir + "/cuckoo_read_benchmark" +
-    std::to_string(num/1000000) + "Mkeys";
+    ToString(num/1000000) + "Mkeys";
 }
 
 // Create last level file as we are interested in measuring performance of

table/plain_table_reader.cc

@@ -36,6 +36,7 @@
 #include "util/murmurhash.h"
 #include "util/perf_context_imp.h"
 #include "util/stop_watch.h"
+#include "util/string_util.h"
 
 
 namespace rocksdb {
@@ -380,14 +381,14 @@ Status PlainTableReader::PopulateIndex(TableProperties* props,
   // Fill two table properties.
   if (!index_in_file) {
     props->user_collected_properties["plain_table_hash_table_size"] =
-        std::to_string(index_.GetIndexSize() * PlainTableIndex::kOffsetLen);
+        ToString(index_.GetIndexSize() * PlainTableIndex::kOffsetLen);
     props->user_collected_properties["plain_table_sub_index_size"] =
-        std::to_string(index_.GetSubIndexSize());
+        ToString(index_.GetSubIndexSize());
   } else {
     props->user_collected_properties["plain_table_hash_table_size"] =
-        std::to_string(0);
+        ToString(0);
     props->user_collected_properties["plain_table_sub_index_size"] =
-        std::to_string(0);
+        ToString(0);
   }
 
   return Status::OK();

table/table_properties.cc

@@ -7,6 +7,8 @@
 #include "rocksdb/table_properties.h"
 #include "rocksdb/iterator.h"
 #include "rocksdb/env.h"
+#include "port/port.h"
+#include "util/string_util.h"
 
 namespace rocksdb {
 
@@ -31,7 +33,7 @@ namespace {
       const std::string& prop_delim,
       const std::string& kv_delim) {
     AppendProperty(
-        props, key, std::to_string(value), prop_delim, kv_delim
+        props, key, ToString(value), prop_delim, kv_delim
     );
   }
 }

table/table_test.cc

@@ -1039,9 +1039,9 @@ TEST(TablePropertyTest, PrefixScanTest) {
              pos->first.compare(0, prefix.size(), prefix) == 0;
          ++pos) {
       ++num;
-      auto key = prefix + "." + std::to_string(num);
+      auto key = prefix + "." + ToString(num);
       ASSERT_EQ(key, pos->first);
-      ASSERT_EQ(std::to_string(num), pos->second);
+      ASSERT_EQ(ToString(num), pos->second);
     }
     ASSERT_EQ(3, num);
   }

tools/db_sanity_test.cc

@@ -17,6 +17,8 @@
 #include "rocksdb/table.h"
 #include "rocksdb/slice_transform.h"
 #include "rocksdb/filter_policy.h"
+#include "port/port.h"
+#include "util/string_util.h"
 
 namespace rocksdb {
 
@@ -43,8 +45,8 @@ class SanityTest {
       return s;
     }
     for (int i = 0; i < 1000000; ++i) {
-      std::string k = "key" + std::to_string(i);
+      std::string k = "key" + ToString(i);
-      std::string v = "value" + std::to_string(i);
+      std::string v = "value" + ToString(i);
       s = db->Put(WriteOptions(), Slice(k), Slice(v));
       if (!s.ok()) {
         return s;
@@ -61,8 +63,8 @@ class SanityTest {
       return s;
     }
     for (int i = 0; i < 1000000; ++i) {
-      std::string k = "key" + std::to_string(i);
+      std::string k = "key" + ToString(i);
-      std::string v = "value" + std::to_string(i);
+      std::string v = "value" + ToString(i);
       std::string result;
       s = db->Get(ReadOptions(), Slice(k), &result);
       if (!s.ok()) {

tools/db_stress.cc

@@ -52,6 +52,7 @@ int main() {
 #include "util/logging.h"
 #include "hdfs/env_hdfs.h"
 #include "utilities/merge_operators.h"
+#include "util/string_util.h"
 
 using GFLAGS::ParseCommandLineFlags;
 using GFLAGS::RegisterFlagValidator;
@@ -801,23 +802,23 @@ class StressTest {
     options_table_ = {
       {"write_buffer_size",
         {
-          std::to_string(FLAGS_write_buffer_size),
+          ToString(FLAGS_write_buffer_size),
-          std::to_string(FLAGS_write_buffer_size * 2),
+          ToString(FLAGS_write_buffer_size * 2),
-          std::to_string(FLAGS_write_buffer_size * 4)
+          ToString(FLAGS_write_buffer_size * 4)
         }
       },
       {"max_write_buffer_number",
         {
-          std::to_string(FLAGS_max_write_buffer_number),
+          ToString(FLAGS_max_write_buffer_number),
-          std::to_string(FLAGS_max_write_buffer_number * 2),
+          ToString(FLAGS_max_write_buffer_number * 2),
-          std::to_string(FLAGS_max_write_buffer_number * 4)
+          ToString(FLAGS_max_write_buffer_number * 4)
         }
       },
       {"arena_block_size",
         {
-          std::to_string(Options().arena_block_size),
+          ToString(Options().arena_block_size),
-          std::to_string(FLAGS_write_buffer_size / 4),
+          ToString(FLAGS_write_buffer_size / 4),
-          std::to_string(FLAGS_write_buffer_size / 8),
+          ToString(FLAGS_write_buffer_size / 8),
         }
       },
       {"memtable_prefix_bloom_bits", {"0", "8", "10"}},
@@ -825,7 +826,7 @@ class StressTest {
       {"memtable_prefix_bloom_huge_page_tlb_size",
         {
           "0",
-          std::to_string(2 * 1024 * 1024)
+          ToString(2 * 1024 * 1024)
         }
       },
       {"max_successive_merges", {"0", "2", "4"}},
@@ -837,70 +838,70 @@ class StressTest {
       {"hard_rate_limit", {"0", "1.1", "2.0"}},
       {"level0_file_num_compaction_trigger",
         {
-          std::to_string(FLAGS_level0_file_num_compaction_trigger),
+          ToString(FLAGS_level0_file_num_compaction_trigger),
-          std::to_string(FLAGS_level0_file_num_compaction_trigger + 2),
+          ToString(FLAGS_level0_file_num_compaction_trigger + 2),
-          std::to_string(FLAGS_level0_file_num_compaction_trigger + 4),
+          ToString(FLAGS_level0_file_num_compaction_trigger + 4),
         }
       },
       {"level0_slowdown_writes_trigger",
         {
-          std::to_string(FLAGS_level0_slowdown_writes_trigger),
+          ToString(FLAGS_level0_slowdown_writes_trigger),
-          std::to_string(FLAGS_level0_slowdown_writes_trigger + 2),
+          ToString(FLAGS_level0_slowdown_writes_trigger + 2),
-          std::to_string(FLAGS_level0_slowdown_writes_trigger + 4),
+          ToString(FLAGS_level0_slowdown_writes_trigger + 4),
         }
       },
       {"level0_stop_writes_trigger",
         {
-          std::to_string(FLAGS_level0_stop_writes_trigger),
+          ToString(FLAGS_level0_stop_writes_trigger),
-          std::to_string(FLAGS_level0_stop_writes_trigger + 2),
+          ToString(FLAGS_level0_stop_writes_trigger + 2),
-          std::to_string(FLAGS_level0_stop_writes_trigger + 4),
+          ToString(FLAGS_level0_stop_writes_trigger + 4),
         }
       },
       {"max_grandparent_overlap_factor",
         {
-          std::to_string(Options().max_grandparent_overlap_factor - 5),
+          ToString(Options().max_grandparent_overlap_factor - 5),
-          std::to_string(Options().max_grandparent_overlap_factor),
+          ToString(Options().max_grandparent_overlap_factor),
-          std::to_string(Options().max_grandparent_overlap_factor + 5),
+          ToString(Options().max_grandparent_overlap_factor + 5),
         }
       },
       {"expanded_compaction_factor",
         {
-          std::to_string(Options().expanded_compaction_factor - 5),
+          ToString(Options().expanded_compaction_factor - 5),
-          std::to_string(Options().expanded_compaction_factor),
+          ToString(Options().expanded_compaction_factor),
-          std::to_string(Options().expanded_compaction_factor + 5),
+          ToString(Options().expanded_compaction_factor + 5),
         }
       },
       {"source_compaction_factor",
         {
-          std::to_string(Options().source_compaction_factor),
+          ToString(Options().source_compaction_factor),
-          std::to_string(Options().source_compaction_factor * 2),
+          ToString(Options().source_compaction_factor * 2),
-          std::to_string(Options().source_compaction_factor * 4),
+          ToString(Options().source_compaction_factor * 4),
         }
       },
       {"target_file_size_base",
         {
-          std::to_string(FLAGS_target_file_size_base),
+          ToString(FLAGS_target_file_size_base),
-          std::to_string(FLAGS_target_file_size_base * 2),
+          ToString(FLAGS_target_file_size_base * 2),
-          std::to_string(FLAGS_target_file_size_base * 4),
+          ToString(FLAGS_target_file_size_base * 4),
         }
       },
       {"target_file_size_multiplier",
         {
-          std::to_string(FLAGS_target_file_size_multiplier),
+          ToString(FLAGS_target_file_size_multiplier),
           "1",
           "2",
         }
       },
       {"max_bytes_for_level_base",
         {
-          std::to_string(FLAGS_max_bytes_for_level_base / 2),
+          ToString(FLAGS_max_bytes_for_level_base / 2),
-          std::to_string(FLAGS_max_bytes_for_level_base),
+          ToString(FLAGS_max_bytes_for_level_base),
-          std::to_string(FLAGS_max_bytes_for_level_base * 2),
+          ToString(FLAGS_max_bytes_for_level_base * 2),
         }
       },
       {"max_bytes_for_level_multiplier",
         {
-          std::to_string(FLAGS_max_bytes_for_level_multiplier),
+          ToString(FLAGS_max_bytes_for_level_multiplier),
           "1",
           "2",
         }
@@ -1377,7 +1378,7 @@ class StressTest {
           // drop column family and then create it again (can't drop default)
           int cf = thread->rand.Next() % (FLAGS_column_families - 1) + 1;
           std::string new_name =
-              std::to_string(new_column_family_name_.fetch_add(1));
+              ToString(new_column_family_name_.fetch_add(1));
           {
             MutexLock l(thread->shared->GetMutex());
             fprintf(
@@ -1881,7 +1882,7 @@ class StressTest {
         cf_descriptors.emplace_back(name, ColumnFamilyOptions(options_));
       }
       while (cf_descriptors.size() < (size_t)FLAGS_column_families) {
-        std::string name = std::to_string(new_column_family_name_.load());
+        std::string name = ToString(new_column_family_name_.load());
         new_column_family_name_++;
         cf_descriptors.emplace_back(name, ColumnFamilyOptions(options_));
         column_family_names_.push_back(name);

util/autovector_test.cc

@@ -53,7 +53,7 @@ TEST(AutoVectorTest, EmplaceBack) {
   autovector<ValType, kSize> vec;
 
   for (size_t i = 0; i < 1000 * kSize; ++i) {
-    vec.emplace_back(i, std::to_string(i + 123));
+    vec.emplace_back(i, ToString(i + 123));
     ASSERT_TRUE(!vec.empty());
     if (i < kSize) {
       ASSERT_TRUE(vec.only_in_stack());
@@ -63,7 +63,7 @@ TEST(AutoVectorTest, EmplaceBack) {
 
     ASSERT_EQ(i + 1, vec.size());
     ASSERT_EQ(i, vec[i].first);
-    ASSERT_EQ(std::to_string(i + 123), vec[i].second);
+    ASSERT_EQ(ToString(i + 123), vec[i].second);
   }
 
   vec.clear();
@@ -129,7 +129,7 @@ TEST(AutoVectorTest, CopyAndAssignment) {
 TEST(AutoVectorTest, Iterators) {
   autovector<std::string, kSize> vec;
   for (size_t i = 0; i < kSize * 1000; ++i) {
-    vec.push_back(std::to_string(i));
+    vec.push_back(ToString(i));
   }
 
   // basic operator test

util/benchharness.cc

@@ -16,6 +16,7 @@
 #include <string>
 #include <utility>
 #include <vector>
+#include "util/string_util.h"
 
 #ifndef GFLAGS
 bool FLAGS_benchmark = false;
@@ -283,7 +284,7 @@ static const ScaleInfo kMetricSuffixes[] {
 static string HumanReadable(double n, unsigned int decimals,
                             const ScaleInfo* scales) {
   if (std::isinf(n) || std::isnan(n)) {
-    return std::to_string(n);
+    return ToString(n);
   }
 
   const double absValue = fabs(n);

util/cache_test.cc

@@ -133,7 +133,7 @@ TEST(CacheTest, UsageTest) {
 
   // make sure the cache will be overloaded
   for (uint64_t i = 1; i < kCapacity; ++i) {
-    auto key = std::to_string(i);
+    auto key = ToString(i);
     cache->Release(
         cache->Insert(key, (void*)value, key.size() + 5, dumbDeleter)
     );
@@ -402,13 +402,13 @@ TEST(CacheTest, BadEviction) {
 
   // Insert n+1 entries, but not releasing.
   for (int i = 0; i < n+1; i++) {
-    std::string key = std::to_string(i+1);
+    std::string key = ToString(i+1);
     handles[i] = cache->Insert(key, new Value(i+1), 1, &deleter);
   }
 
   // Guess what's in the cache now?
   for (int i = 0; i < n+1; i++) {
-    std::string key = std::to_string(i+1);
+    std::string key = ToString(i+1);
     auto h = cache->Lookup(key);
     std::cout << key << (h?" found\n":" not found\n");
     // Only the first entry should be missing

util/env_hdfs.cc

@@ -443,7 +443,7 @@ Status HdfsEnv::NewDirectory(const std::string& name,
       Log(InfoLogLevel::FATAL_LEVEL,
           mylog, "NewDirectory hdfsExists call failed");
       throw HdfsFatalException("hdfsExists call failed with error " +
-                               std::to_string(value) + " on path " + name +
+                               ToString(value) + " on path " + name +
                                ".\n");
   }
 }
@@ -460,7 +460,7 @@ bool HdfsEnv::FileExists(const std::string& fname) {
       Log(InfoLogLevel::FATAL_LEVEL,
           mylog, "FileExists hdfsExists call failed");
       throw HdfsFatalException("hdfsExists call failed with error " +
-                               std::to_string(value) + " on path " + fname +
+                               ToString(value) + " on path " + fname +
                                ".\n");
   }
 }
@@ -499,7 +499,7 @@ Status HdfsEnv::GetChildren(const std::string& path,
     Log(InfoLogLevel::FATAL_LEVEL, mylog,
         "GetChildren hdfsExists call failed");
     throw HdfsFatalException("hdfsExists call failed with error " +
-                             std::to_string(value) + ".\n");
+                             ToString(value) + ".\n");
   }
   return Status::OK();
 }
@@ -530,7 +530,7 @@ Status HdfsEnv::CreateDirIfMissing(const std::string& name) {
       Log(InfoLogLevel::FATAL_LEVEL, mylog,
           "CreateDirIfMissing hdfsExists call failed");
       throw HdfsFatalException("hdfsExists call failed with error " +
-                               std::to_string(value) + ".\n");
+                               ToString(value) + ".\n");
   }
 };
 

util/env_test.cc

@@ -603,7 +603,8 @@ TEST(EnvPosixTest, RandomAccessUniqueIDConcurrent) {
   // Create the files
   std::vector<std::string> fnames;
   for (int i = 0; i < 1000; ++i) {
-    fnames.push_back(GetOnDiskTestDir() + "/" + "testfile" + std::to_string(i));
+    fnames.push_back(
+        GetOnDiskTestDir() + "/" + "testfile" + ToString(i));
 
     // Create file.
     unique_ptr<WritableFile> wfile;

util/ldb_cmd.cc

@@ -1293,15 +1293,15 @@ void ChangeCompactionStyleCommand::DoCommand() {
     // level 0 should have only 1 file
     if (i == 0 && num_files != 1) {
       exec_state_ = LDBCommandExecuteResult::FAILED("Number of db files at "
-        "level 0 after compaction is " + std::to_string(num_files) +
+        "level 0 after compaction is " + ToString(num_files) +
         ", not 1.\n");
       return;
     }
     // other levels should have no file
     if (i > 0 && num_files != 0) {
       exec_state_ = LDBCommandExecuteResult::FAILED("Number of db files at "
-        "level " + std::to_string(i) + " after compaction is " +
+        "level " + ToString(i) + " after compaction is " +
-        std::to_string(num_files) + ", not 0.\n");
+        ToString(num_files) + ", not 0.\n");
       return;
     }
   }

util/slice.cc

@@ -9,6 +9,7 @@
 
 #include "rocksdb/slice_transform.h"
 #include "rocksdb/slice.h"
+#include "util/string_util.h"
 
 namespace rocksdb {
 
@@ -22,7 +23,7 @@ class FixedPrefixTransform : public SliceTransform {
  public:
   explicit FixedPrefixTransform(size_t prefix_len)
       : prefix_len_(prefix_len),
-        name_("rocksdb.FixedPrefix." + std::to_string(prefix_len_)) {}
+        name_("rocksdb.FixedPrefix." + ToString(prefix_len_)) {}
 
   virtual const char* Name() const { return name_.c_str(); }
 

util/string_util.h

@@ -12,4 +12,17 @@ namespace rocksdb {
 
 extern std::vector<std::string> StringSplit(const std::string& arg, char delim);
 
+template <typename T>
+inline std::string ToString(T value) {
+#ifndef OS_ANDROID
+  return std::to_string(value);
+#else
+  // Andorid doesn't support all of C++11, std::to_string() being
+  // one of the not supported features.
+  std::ostringstream os;
+  os << value;
+  return os.str();
+#endif
+}
+
 }  // namespace rocksdb

util/testharness.h

@@ -17,6 +17,7 @@
 #include "rocksdb/env.h"
 #include "rocksdb/slice.h"
 #include "util/random.h"
+#include "util/string_util.h"
 
 namespace rocksdb {
 namespace test {