diff options
Diffstat (limited to 'BackEnd/Timeline/Services/Data/DataManager.cs')
| -rw-r--r-- | BackEnd/Timeline/Services/Data/DataManager.cs | 93 |
1 files changed, 29 insertions, 64 deletions
diff --git a/BackEnd/Timeline/Services/Data/DataManager.cs b/BackEnd/Timeline/Services/Data/DataManager.cs index d9a4491d..9de17da3 100644 --- a/BackEnd/Timeline/Services/Data/DataManager.cs +++ b/BackEnd/Timeline/Services/Data/DataManager.cs @@ -1,73 +1,40 @@ using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging;
using System;
using System.Linq;
+using System.Threading;
using System.Threading.Tasks;
using Timeline.Entities;
namespace Timeline.Services.Data
{
- /// <summary>
- /// A data manager controlling data.
- /// </summary>
- /// <remarks>
- /// Identical data will be saved as one copy and return the same tag.
- /// Every data has a ref count. When data is retained, ref count increase.
- /// When data is freed, ref count decease. If ref count is decreased
- /// to 0, the data entry will be destroyed and no longer occupy space.
- /// </remarks>
- public interface IDataManager
- {
- /// <summary>
- /// Saves the data to a new entry if it does not exist,
- /// increases its ref count and returns a tag to the entry.
- /// </summary>
- /// <param name="data">The data. Can't be null.</param>
- /// <returns>The tag of the created entry.</returns>
- /// <exception cref="ArgumentNullException">Thrown when <paramref name="data"/> is null.</exception>
- public Task<string> RetainEntry(byte[] data);
-
- /// <summary>
- /// Decrease the the ref count of the entry.
- /// Remove it if ref count is zero.
- /// </summary>
- /// <param name="tag">The tag of the entry.</param>
- /// <exception cref="ArgumentNullException">Thrown when <paramref name="tag"/> is null.</exception>
- /// <remarks>
- /// It's no-op if entry with tag does not exist.
- /// </remarks>
- public Task FreeEntry(string tag);
-
- /// <summary>
- /// Retrieve the entry with given tag. If not exist, returns null.
- /// </summary>
- /// <param name="tag">The tag of the entry.</param>
- /// <returns>The data of the entry. If not exist, returns null.</returns>
- /// <exception cref="ArgumentNullException">Thrown when <paramref name="tag"/> is null.</exception>
- public Task<byte[]?> GetEntry(string tag);
- }
-
public class DataManager : IDataManager
{
+ private readonly ILogger<DataManager> _logger;
private readonly DatabaseContext _database;
private readonly IETagGenerator _eTagGenerator;
- public DataManager(DatabaseContext database, IETagGenerator eTagGenerator)
+ public DataManager(ILogger<DataManager> logger, DatabaseContext database, IETagGenerator eTagGenerator)
{
+ _logger = logger;
_database = database;
_eTagGenerator = eTagGenerator;
}
- public async Task<string> RetainEntry(byte[] data)
+ public async Task<string> RetainEntry(byte[] data, CancellationToken cancellationToken = default)
{
if (data == null)
throw new ArgumentNullException(nameof(data));
- var tag = await _eTagGenerator.Generate(data);
+ var tag = await _eTagGenerator.GenerateETagAsync(data, cancellationToken);
+
+ var entity = await _database.Data.Where(d => d.Tag == tag).SingleOrDefaultAsync(cancellationToken);
+ bool create;
- var entity = await _database.Data.Where(d => d.Tag == tag).SingleOrDefaultAsync();
if (entity == null)
{
+ create = true;
entity = new DataEntity
{
Tag = tag,
@@ -78,42 +45,54 @@ namespace Timeline.Services.Data }
else
{
+ create = false;
entity.Ref += 1;
}
- await _database.SaveChangesAsync();
+ await _database.SaveChangesAsync(cancellationToken);
+
+ _logger.LogInformation(create ? Resource.LogDataManagerRetainEntryCreate : Resource.LogDataManagerRetainEntryAddRefCount, tag);
return tag;
}
- public async Task FreeEntry(string tag)
+ public async Task FreeEntry(string tag, CancellationToken cancellationToken = default)
{
if (tag == null)
throw new ArgumentNullException(nameof(tag));
- var entity = await _database.Data.Where(d => d.Tag == tag).SingleOrDefaultAsync();
+ var entity = await _database.Data.Where(d => d.Tag == tag).SingleOrDefaultAsync(cancellationToken);
if (entity != null)
{
+ bool remove;
+
if (entity.Ref == 1)
{
+ remove = true;
_database.Data.Remove(entity);
}
else
{
+ remove = false;
entity.Ref -= 1;
}
- await _database.SaveChangesAsync();
+ await _database.SaveChangesAsync(cancellationToken);
+ _logger.LogInformation(remove ? Resource.LogDataManagerFreeEntryRemove : Resource.LogDataManagerFreeEntryDecreaseRefCount, tag);
+ }
+ else
+ {
+ _logger.LogInformation(Resource.LogDataManagerFreeEntryNotExist, tag);
}
}
- public async Task<byte[]?> GetEntry(string tag)
+ public async Task<byte[]?> GetEntry(string tag, CancellationToken cancellationToken = default)
{
if (tag == null)
throw new ArgumentNullException(nameof(tag));
- var entity = await _database.Data.Where(d => d.Tag == tag).Select(d => new { d.Data }).SingleOrDefaultAsync();
+ var entity = await _database.Data.Where(d => d.Tag == tag).Select(d => new { d.Data }).SingleOrDefaultAsync(cancellationToken);
if (entity is null)
return null;
@@ -121,18 +100,4 @@ namespace Timeline.Services.Data return entity.Data;
}
}
-
- public static class DataManagerExtensions
- {
- /// <summary>
- /// Try to get an entry and throw <see cref="DatabaseCorruptedException"/> if not exist.
- /// </summary>
- public static async Task<byte[]> GetEntryAndCheck(this IDataManager dataManager, string tag, string notExistMessage)
- {
- var data = await dataManager.GetEntry(tag);
- if (data is null)
- throw new DatabaseCorruptedException($"Can't get data of tag {tag}. {notExistMessage}");
- return data;
- }
- }
}
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