Open cache in r/o mode on no space left errors (#1375)

Since protected cache could be used as a static cache it is expected
to be able to use it even when there is no available space on device.
But when protected cache is being open in R/W mode levelDb may try to
create some files and this failure would be treated later as a corrupted
cache.
Instead, on `no space left` errors we will try to open the cache again
but in read-only mode to enforce static behavior.

Relates-To: OLPSUP-21193
Signed-off-by: Andrey Kashcheev <ext-andrey.kashcheev@here.com>

olp-cpp-sdk-core/src/cache/DefaultCacheImpl.cpp

@@ -128,6 +128,7 @@ olp::cache::DefaultCache::StorageOpenResult ToStorageOpenResult(
     case olp::cache::OpenResult::Fail:
       return StorageOpenResult::OpenDiskPathFailure;
     case olp::cache::OpenResult::Corrupted:
+    case olp::cache::OpenResult::IOError:
       return StorageOpenResult::ProtectedCacheCorrupted;
     case olp::cache::OpenResult::Repaired:
     case olp::cache::OpenResult::Success:
@@ -847,12 +848,27 @@ DefaultCache::StorageOpenResult DefaultCacheImpl::SetupProtectedCache() {
                          "r/o mode, disk_path_protected='%s'",
                          settings_.disk_path_protected.get().c_str());
       open_mode = static_cast<OpenOptions>(open_mode | OpenOptions::ReadOnly);
+      is_read_only = true;
     }
   }
 
   auto status = protected_cache_->Open(
       settings_.disk_path_protected.get(), settings_.disk_path_protected.get(),
       protected_storage_settings, open_mode, false);
+
+  if (status == OpenResult::IOError && !is_read_only) {
+    OLP_SDK_LOG_INFO_F(
+        kLogTag,
+        "Failed to open in r/w mode, trying r/o, disk_path_protected='%s'",
+        settings_.disk_path_protected.get().c_str());
+
+    open_mode = static_cast<OpenOptions>(open_mode | OpenOptions::ReadOnly);
+    status =
+        protected_cache_->Open(settings_.disk_path_protected.get(),
+                               settings_.disk_path_protected.get(),
+                               protected_storage_settings, open_mode, false);
+  }
+
   if (status != OpenResult::Success) {
     OLP_SDK_LOG_ERROR_F(kLogTag, "Failed to open protected cache %s",
                         settings_.disk_path_protected.get().c_str());

olp-cpp-sdk-core/src/cache/DiskCache.cpp

@@ -247,6 +247,13 @@ OpenResult DiskCache::Open(const std::string& data_path,
 
   if (status.IsCorruption() || status.IsIOError()) {
     if (is_read_only || !repair_if_broken) {
+      if (status.IsIOError()) {
+        OLP_SDK_LOG_ERROR_F(
+            kLogTag, "Open: IO error, cache_path='%s', error='%s'",
+            versioned_data_path.c_str(), status.ToString().c_str());
+        return OpenResult::IOError;
+      }
+
       OLP_SDK_LOG_ERROR_F(
           kLogTag, "Open: cache corrupted, cache_path='%s', error='%s'",
           versioned_data_path.c_str(), status.ToString().c_str());

olp-cpp-sdk-core/src/cache/DiskCache.h

@@ -57,6 +57,8 @@ enum class OpenResult {
   Fail,
   /// The store was corrupted or store compaction was interrupted.
   Corrupted,
+  /// Opening the store failed due to IO error.
+  IOError,
   /// The store was corrupted and has been repaired. Internal integrity might be
   /// broken.
   Repaired,