Address code review feedback: retry loop, comment cleanup, error code improvements

Agent-Logs-Url: https://github.com/XRPLF/rippled/sessions/629eace2-9c23-40d9-89f5-9ef3099cdf14

Co-authored-by: mvadari <8029314+mvadari@users.noreply.github.com>

src/libxrpl/basics/FileUtilities.cpp

@@ -35,7 +35,7 @@ getFileContents(
 
     if (!fileStream)
     {
-        ec = make_error_code(static_cast<std::errc>(errno));
+        ec.assign(errno, std::generic_category());
         return {};
     }
 
@@ -44,7 +44,7 @@ getFileContents(
 
     if (fileStream.bad())
     {
-        ec = make_error_code(static_cast<std::errc>(errno));
+        ec.assign(errno, std::generic_category());
         return {};
     }
 

src/test/basics/FileUtilities_test.cpp

@@ -44,7 +44,7 @@ public:
         {
             // Test with small max
             auto const bad = getFileContents(ec, path, 16);
-            BEAST_EXPECT(ec && ec.value() == static_cast<int>(std::errc::file_too_large));
+            BEAST_EXPECT(ec && ec == std::errc::file_too_large);
             BEAST_EXPECT(bad.empty());
         }
     }

src/xrpld/app/misc/SHAMapStoreImp.cpp

@@ -475,9 +475,21 @@ SHAMapStoreImp::makeBackendRotating(std::string path)
     {
         std::filesystem::path const p = get(section, "path");
         std::random_device rd;
-        std::ostringstream oss;
-        oss << std::hex << std::setfill('0') << std::setw(8) << rd() << std::setw(8) << rd();
-        newPath = (p / dbPrefix_).string() + "." + oss.str();
+        constexpr std::size_t maxAttempts = 100;
+        for (std::size_t attempt = 0; attempt < maxAttempts; ++attempt)
+        {
+            std::ostringstream oss;
+            oss << std::hex << std::setfill('0') << std::setw(8) << rd() << std::setw(8) << rd();
+            auto const candidate =
+                std::filesystem::path((p / dbPrefix_).string() + "." + oss.str());
+            if (!std::filesystem::exists(candidate))
+            {
+                newPath = candidate;
+                break;
+            }
+        }
+        if (newPath.empty())
+            Throw<std::runtime_error>("Unable to generate a unique rotating backend path");
     }
     section.set("path", newPath.string());
 

src/xrpld/core/Config.h

@@ -10,7 +10,7 @@
 #include <xrpl/rdb/DatabaseCon.h>
 
 #include <cstdint>
-#include <filesystem>  // VFALCO FIX: This include should not be here
+#include <filesystem>
 #include <optional>
 #include <string>
 #include <unordered_set>