refactor: hide BlobDescriptor implementation constants

Author: Smith-Cruise

include/paimon/data/blob_descriptor.h

@@ -79,9 +79,6 @@ class PAIMON_EXPORT BlobDescriptor {
         : version_(version), uri_(uri), offset_(offset), length_(length) {}
 
  private:
-    static constexpr int64_t kMagic = 0x424C4F4244455343l;
-    /// one byte for version, eight bytes for magic number.
-    static constexpr uint64_t kMinDescriptorLength = 9;
     static constexpr int8_t kCurrentVersion = 2;
 
     const int8_t version_ = kCurrentVersion;

src/paimon/common/data/blob_descriptor.cpp

@@ -31,6 +31,13 @@
 #include "paimon/status.h"
 
 namespace paimon {
+namespace {
+
+constexpr int64_t kMagic = 0x424C4F4244455343l;
+// One byte for version, eight bytes for magic number.
+constexpr uint64_t kMinDescriptorLength = 9;
+
+}  // namespace
 
 Result<std::unique_ptr<BlobDescriptor>> BlobDescriptor::Create(const std::string& uri,
                                                                int64_t offset, int64_t length) {