/// <summary>
/// Initializes a new instance of the <see cref="JsonStoreWriter"/> class.
/// </summary>
/// <param name="name">The name of the application that generated the persisted files, or the root name of the files.</param>
/// <param name="path">The directory in which the main persisted file resides or will reside, or null to create a volatile data store.</param>
/// <param name="createSubdirectory">If true, a numbered subdirectory is created for this store.</param>
/// <param name="extension">The extension for the underlying file.</param>
public JsonStoreWriter(string name, string path, bool createSubdirectory = true, string extension = DefaultExtension)
: base(extension)
{
ushort id = 0;
this.Name = name;
this.Path = System.IO.Path.GetFullPath(path);
if (createSubdirectory)
{
// if the root directory already exists, look for the next available id
if (Directory.Exists(this.Path))
{
var existingIds = Directory.EnumerateDirectories(this.Path, this.Name + ".????")
.Select(d => d.Split('.').Last())
.Where(n => ushort.TryParse(n, out ushort i))
.Select(n => ushort.Parse(n));
id = (ushort)(existingIds.Count() == 0 ? 0 : existingIds.Max() + 1);
}
this.Path = System.IO.Path.Combine(this.Path, $"{this.Name}.{id:0000}");
}
if (!Directory.Exists(this.Path))
{
Directory.CreateDirectory(this.Path);
}
string dataPath = System.IO.Path.Combine(this.Path, PsiStoreCommon.GetDataFileName(this.Name) + this.Extension);
this.streamWriter = File.CreateText(dataPath);
this.jsonWriter = new JsonTextWriter(this.streamWriter);
this.jsonWriter.WriteStartArray();
}
private void WriteCatalog()
{
string metadataPath = System.IO.Path.Combine(this.Path, PsiStoreCommon.GetCatalogFileName(this.Name) + this.Extension);
using (var file = File.CreateText(metadataPath))
using (var writer = new JsonTextWriter(file))
{
this.Serializer.Serialize(writer, this.catalog.Values.ToList());
}
}
/// <summary>
/// Initializes a new instance of the <see cref="JsonStoreReader"/> class.
/// </summary>
/// <param name="name">The name of the application that generated the persisted files, or the root name of the files.</param>
/// <param name="path">The directory in which the main persisted file resides or will reside, or null to create a volatile data store.</param>
/// <param name="extension">The extension for the underlying file.</param>
public JsonStoreReader(string name, string path, string extension = DefaultExtension)
: base(extension)
{
this.Name = name;
this.Path = PsiStoreCommon.GetPathToLatestVersion(name, path);
// load catalog
string metadataPath = System.IO.Path.Combine(this.Path, PsiStoreCommon.GetCatalogFileName(this.Name) + this.Extension);
using (var file = File.OpenText(metadataPath))
using (var reader = new JsonTextReader(file))
{
this.catalog = this.Serializer.Deserialize <List <JsonStreamMetadata> >(reader);
}
// compute originating time interval
this.originatingTimeInterval = TimeInterval.Empty;
foreach (var metadata in this.catalog)
{
var metadataTimeInterval = new TimeInterval(metadata.FirstMessageOriginatingTime, metadata.LastMessageOriginatingTime);
this.originatingTimeInterval = TimeInterval.Coverage(new TimeInterval[] { this.originatingTimeInterval, metadataTimeInterval });
}
}
/// <summary>
/// Seek to envelope in stream according to specified replay descriptor.
/// </summary>
/// <param name="descriptor">The replay descriptor.</param>
public void Seek(ReplayDescriptor descriptor)
{
this.descriptor = descriptor;
// load data
string dataPath = System.IO.Path.Combine(this.Path, PsiStoreCommon.GetDataFileName(this.Name) + this.Extension);
this.streamReader?.Dispose();
this.streamReader = File.OpenText(dataPath);
this.jsonReader = new JsonTextReader(this.streamReader);
// iterate through data store until we either reach the end or we find the start of the replay descriptor
while (this.jsonReader.Read())
{
// data stores are arrays of messages, messages start as objects
if (this.jsonReader.TokenType == JsonToken.StartObject)
{
// read envelope
if (!this.jsonReader.Read() || !this.ReadEnvelope(out this.envelope))
{
throw new InvalidDataException("Messages must be an ordered object: {\"Envelope\": <Envelope>, \"Data\": <Data>}. Deserialization needs to read the envelope before the data to know what type of data to deserialize.");
}
if (this.descriptor.Interval.Left < this.envelope.OriginatingTime)
{
// found start of interval
break;
}
// skip data
if (!this.ReadData(out this.data))
{
throw new InvalidDataException("Messages must be an ordered object: {\"Envelope\": <Envelope>, \"Data\": <Data>}. Deserialization needs to read the envelope before the data to know what type of data to deserialize.");
}
}
}
}
/// <summary>
/// Indicates whether the specified \psi store file exists.
/// </summary>
/// <param name="name">The name of the store to check.</param>
/// <param name="path">The path of the store to check.</param>
/// <returns>Returns true if the store exists.</returns>
public static bool Exists(string name, string path)
{
return((path == null) ? InfiniteFileReader.IsActive(PsiStoreCommon.GetCatalogFileName(name), path) : PsiStoreCommon.TryGetPathToLatestVersion(name, path, out _));
}
