Fixing some compile issues for alpine and centos, also fix endian issue for FLASH hashslot prefix

pkg/docker/Dockerfile_Alpine

@@ -1,4 +1,4 @@
-FROM alpine:3.12
+FROM alpine:3.18
 # add our user and group first to make sure their IDs get assigned consistently, regardless of whatever dependencies get added
 RUN addgroup -S -g 1000 keydb && adduser -S -G keydb -u 999 keydb
 RUN mkdir -p /etc/keydb

src/Makefile

@@ -358,6 +358,7 @@ endif
 OS := $(shell cat /etc/os-release | grep ID= | head -n 1 | cut -d'=' -f2)
 ifeq ($(OS),alpine)
     FINAL_CXXFLAGS+=-DUNW_LOCAL_ONLY
+	FINAL_CXXFLAGS+=-DALPINE
     FINAL_LIBS += -lunwind
 endif
 

src/readwritelock.h

@@ -42,9 +42,9 @@ class readWriteLock {
             while (m_readCount > 0)
                 m_cv.wait(rm);
             if (exclusive) {
-                /* Another thread might have the write lock while we have the read lock
-                but won't be able to release it until they can acquire the read lock
-                so release the read lock and try again instead of waiting to avoid deadlock */
+                /* Another thread might have the write lock while we have the internal lock
+                but won't be able to release it until they can acquire the internal lock
+                so release the internal lock and try again instead of waiting to avoid deadlock */
                 while(!m_writeLock.try_lock())
                     m_cv.wait(rm);
             }

src/server.h

@@ -3923,7 +3923,7 @@ void updateActiveReplicaMastersFromRsi(rdbSaveInfo *rsi);
 uint64_t getMvccTstamp();
 void incrementMvccTstamp();
 
-#if __GNUC__ >= 7 && !defined(NO_DEPRECATE_FREE)
+#if __GNUC__ >= 7 && !defined(NO_DEPRECATE_FREE) && !defined(ALPINE)
  [[deprecated]]
 void *calloc(size_t count, size_t size) noexcept;
  [[deprecated]]

src/storage/rocksdb.cpp

@@ -7,6 +7,8 @@
 #include "../cluster.h"
 #include "rocksdbfactor_internal.h"
 
+template class std::basic_string<char>;
+
 static const char keyprefix[] = INTERNAL_KEY_PREFIX;
 
 rocksdb::Options DefaultRocksDBOptions();
@@ -25,7 +27,7 @@ bool FInternalKey(const char *key, size_t cch)
 std::string getPrefix(unsigned int hashslot)
 {
     char *hash_char = (char *)&hashslot;
-    return std::string(hash_char + (sizeof(unsigned int) - 2), 2);
+    return std::string(hash_char, sizeof(unsigned int));
 }
 
 std::string prefixKey(const char *key, size_t cchKey)
@@ -184,7 +186,7 @@ bool RocksDBStorageProvider::enumerate(callback fn) const
         if (FInternalKey(it->key().data(), it->key().size()))
             continue;
         ++count;
-        bool fContinue = fn(it->key().data()+2, it->key().size()-2, it->value().data(), it->value().size());
+        bool fContinue = fn(it->key().data()+sizeof(unsigned int), it->key().size()-sizeof(unsigned int), it->value().data(), it->value().size());
         if (!fContinue)
             break;
     }
@@ -203,17 +205,17 @@ bool RocksDBStorageProvider::enumerate_hashslot(callback fn, unsigned int hashsl
     std::string prefix = getPrefix(hashslot);
     std::unique_ptr<rocksdb::Iterator> it = std::unique_ptr<rocksdb::Iterator>(m_spdb->NewIterator(ReadOptions(), m_spcolfamily.get()));
     size_t count = 0;
-    for (it->Seek(prefix.c_str()); it->Valid(); it->Next()) {
+    for (it->Seek(prefix); it->Valid(); it->Next()) {
         if (FInternalKey(it->key().data(), it->key().size()))
             continue;
-        if (strncmp(it->key().data(),prefix.c_str(),2) != 0)
+        if (*(unsigned int *)it->key().data() != hashslot)
             break;
         ++count;
-        bool fContinue = fn(it->key().data()+2, it->key().size()-2, it->value().data(), it->value().size());
+        bool fContinue = fn(it->key().data()+sizeof(unsigned int), it->key().size()-sizeof(unsigned int), it->value().data(), it->value().size());
         if (!fContinue)
             break;
     }
-    bool full_iter = !it->Valid() || (strncmp(it->key().data(),prefix.c_str(),2) != 0);
+    bool full_iter = !it->Valid() || (*(unsigned int *)it->key().data() != hashslot);
     if (full_iter && count != g_pserver->cluster->slots_keys_count[hashslot])
     {
         printf("WARNING: rocksdb hashslot count mismatch");
@@ -278,7 +280,7 @@ std::vector<std::string> RocksDBStorageProvider::getEvictionCandidates(unsigned
         for (it->Seek(randomHashSlot()); it->Valid() && result.size() < count; it->Next()) {
             if (FInternalKey(it->key().data(), it->key().size()))
                 continue;
-            result.emplace_back(it->key().data() + 2, it->key().size() - 2);
+            result.emplace_back(it->key().data() + sizeof(unsigned int), it->key().size() - sizeof(unsigned int));
         }
     } else {
         std::unique_ptr<rocksdb::Iterator> it = std::unique_ptr<rocksdb::Iterator>(m_spdb->NewIterator(ReadOptions(), m_spexpirecolfamily.get()));

src/storage/rocksdbfactory.cpp

@@ -72,7 +72,7 @@ RocksDBStorageFactory::RocksDBStorageFactory(const char *dbfile, int dbnum, cons
     rocksdb::DB *db = nullptr;
 
     auto options = RocksDbOptions();
-    options.prefix_extractor.reset(rocksdb::NewFixedPrefixTransform(2));
+    options.prefix_extractor.reset(rocksdb::NewFixedPrefixTransform(sizeof(unsigned int)));
 
     for (int idb = 0; idb < dbnum; ++idb)
     {
@@ -196,7 +196,7 @@ IStorage *RocksDBStorageFactory::create(int db, key_load_iterator iter, void *pr
                 printf("\tDatabase %d was not shutdown cleanly, recomputing metrics\n", db);
             fFirstRealKey = false;
             if (iter != nullptr)
-                iter(it->key().data()+2, it->key().size()-2, privdata);
+                iter(it->key().data()+sizeof(unsigned int), it->key().size()-sizeof(unsigned int), privdata);
             ++count;
         }
     }