/// <summary>

/// The default implementation of <see cref="INpgsqlDatabaseInfoFactory"/>, for standard PostgreSQL databases..

/// </summary>

class PostgresDatabaseInfoFactory : INpgsqlDatabaseInfoFactory

{

/// <inheritdoc />

public async Task<NpgsqlDatabaseInfo?> Load(NpgsqlConnection conn, NpgsqlTimeout timeout, bool async)

{

var db = new PostgresDatabaseInfo(conn);

await db.LoadPostgresInfo(conn, timeout, async);

Debug.Assert(db.LongVersion != null);

return db;

}

}

/// <summary>

/// The default implementation of NpgsqlDatabase, for standard PostgreSQL databases.

/// </summary>

class PostgresDatabaseInfo : NpgsqlDatabaseInfo

{

/// <summary>

/// The Npgsql logger instance.

/// </summary>

static readonly NpgsqlLogger Log = NpgsqlLogManager.CreateLogger(nameof(PostgresDatabaseInfo));

/// <summary>

/// The PostgreSQL types detected in the database.

/// </summary>

List<PostgresType>? _types;

/// <inheritdoc />

protected override IEnumerable<PostgresType> GetTypes() => _types ?? Enumerable.Empty<PostgresType>();

/// <summary>

/// The PostgreSQL version string as returned by the version() function. Populated during loading.

/// </summary>

public string LongVersion { get; set; } = default!;

/// <summary>

/// True if the backend is Amazon Redshift; otherwise, false.

/// </summary>

public bool IsRedshift { get; private set; }

/// <inheritdoc />

public override bool SupportsUnlisten => Version >= new Version(6, 4, 0) && !IsRedshift;

/// <summary>

/// True if the 'pg_enum' table includes the 'enumsortorder' column; otherwise, false.

/// </summary>

public virtual bool HasEnumSortOrder => Version >= new Version(9, 1, 0);

/// <summary>

/// True if the 'pg_type' table includes the 'typcategory' column; otherwise, false.

/// </summary>

/// <remarks>

/// pg_type.typcategory is added after 8.4.

/// see: https://www.postgresql.org/docs/8.4/static/catalog-pg-type.html#CATALOG-TYPCATEGORY-TABLE

/// </remarks>

public virtual bool HasTypeCategory => Version >= new Version(8, 4, 0);

internal PostgresDatabaseInfo(NpgsqlConnection conn)

: base(conn.Host!, conn.Port, conn.Database!, ParseServerVersion(conn.PostgresParameters["server_version"]))

{

}

/// <summary>

/// Loads database information from the PostgreSQL database specified by <paramref name="conn"/>.

/// </summary>

/// <param name="conn">The database connection.</param>

/// <param name="timeout">The timeout while loading types from the backend.</param>

/// <param name="async">True to load types asynchronously.</param>

/// <returns>

/// A task representing the asynchronous operation.

/// </returns>

internal async Task LoadPostgresInfo(NpgsqlConnection conn, NpgsqlTimeout timeout, bool async)

{

HasIntegerDateTimes =

conn.PostgresParameters.TryGetValue("integer_datetimes", out var intDateTimes) &&

intDateTimes == "on";

IsRedshift = conn.Settings.ServerCompatibilityMode == ServerCompatibilityMode.Redshift;

_types = await LoadBackendTypes(conn, timeout, async);

}

/// <summary>

/// Generates a raw SQL query string to select type information.

/// </summary>

/// <param name="withRange">True to load range types.</param>

/// <param name="withEnum">True to load enum types.</param>

/// <param name="withEnumSortOrder"></param>

/// <param name="loadTableComposites">True to load table composites.</param>

/// <returns>

/// A raw SQL query string that selects type information.

/// </returns>

/// <remarks>

/// Select all types (base, array which is also base, enum, range, composite).

/// Note that arrays are distinguished from primitive types through them having typreceive=array_recv.

/// Order by primitives first, container later.

/// For arrays and ranges, join in the element OID and type (to filter out arrays of unhandled

/// types).

/// </remarks>

static string GenerateTypesQuery(bool withRange, bool withEnum, bool withEnumSortOrder,

bool loadTableComposites)

=> $@"

/// <summary>

/// Loads type information from the backend specified by <paramref name="conn"/>.

/// </summary>

/// <param name="conn">The database connection.</param>

/// <param name="timeout">The timeout while loading types from the backend.</param>

/// <param name="async">True to load types asynchronously.</param>

/// <returns>

/// A collection of types loaded from the backend.

/// </returns>

/// <exception cref="TimeoutException" />

/// <exception cref="ArgumentOutOfRangeException">Unknown typtype for type '{internalName}' in pg_type: {typeChar}.</exception>

internal async Task<List<PostgresType>> LoadBackendTypes(NpgsqlConnection conn, NpgsqlTimeout timeout, bool async)

{

var commandTimeout = 0; // Default to infinity

if (timeout.IsSet)

{

commandTimeout = (int)timeout.TimeLeft.TotalSeconds;

if (commandTimeout <= 0)

throw new TimeoutException();

}

var typeLoadingQuery = GenerateTypesQuery(SupportsRangeTypes, SupportsEnumTypes, HasEnumSortOrder, conn.Settings.LoadTableComposites);

using var command = new NpgsqlCommand(typeLoadingQuery, conn)

{

CommandTimeout = commandTimeout,

AllResultTypesAreUnknown = true

};

using var reader = async ? await command.ExecuteReaderAsync() : command.ExecuteReader();

var byOID = new Dictionary<uint, PostgresType>();

// First the PostgreSQL version

if (async)

{

await reader.ReadAsync();

LongVersion = reader.GetString(0);

await reader.NextResultAsync();

}

else

{

reader.Read();

LongVersion = reader.GetString(0);

reader.NextResult();

}

// Then load the types

while (async ? await reader.ReadAsync() : reader.Read())

{

timeout.Check();

var ns = reader.GetString("nspname");

var internalName = reader.GetString("typname");

var oid = uint.Parse(reader.GetString("oid"), NumberFormatInfo.InvariantInfo);

Debug.Assert(oid != 0);

var elementOID = reader.IsDBNull("elemtypoid")

? 0

: uint.Parse(reader.GetString("elemtypoid"), NumberFormatInfo.InvariantInfo);

var typeChar = reader.GetChar("typtype");

switch (typeChar)

{

case 'b': // Normal base type

var baseType = new PostgresBaseType(ns, internalName, oid);

byOID[baseType.OID] = baseType;

continue;

case 'a': // Array

{

Debug.Assert(elementOID > 0);

if (!byOID.TryGetValue(elementOID, out var elementPostgresType))

{

Log.Trace($"Array type '{internalName}' refers to unknown element with OID {elementOID}, skipping", conn.ProcessID);

continue;

}

var arrayType = new PostgresArrayType(ns, internalName, oid, elementPostgresType);

byOID[arrayType.OID] = arrayType;

continue;

}

case 'r': // Range

{

Debug.Assert(elementOID > 0);

if (!byOID.TryGetValue(elementOID, out var subtypePostgresType))

{

Log.Trace($"Range type '{internalName}' refers to unknown subtype with OID {elementOID}, skipping", conn.ProcessID);

continue;

}

var rangeType = new PostgresRangeType(ns, internalName, oid, subtypePostgresType);

byOID[rangeType.OID] = rangeType;

continue;

}

case 'e': // Enum

var enumType = new PostgresEnumType(ns, internalName, oid);

byOID[enumType.OID] = enumType;

continue;

case 'c': // Composite

var compositeType = new PostgresCompositeType(ns, internalName, oid);

byOID[compositeType.OID] = compositeType;

continue;

case 'd': // Domain

Debug.Assert(elementOID > 0);

if (!byOID.TryGetValue(elementOID, out var basePostgresType))

{

Log.Trace($"Domain type '{internalName}' refers to unknown base type with OID {elementOID}, skipping", conn.ProcessID);

continue;

}

var domainType = new PostgresDomainType(ns, internalName, oid, basePostgresType, reader.GetString("typnotnull") == "t");

byOID[domainType.OID] = domainType;

continue;

case 'p': // pseudo-type (record, void)

goto case 'b'; // Hack this as a base type

default:

throw new ArgumentOutOfRangeException($"Unknown typtype for type '{internalName}' in pg_type: {typeChar}");

}

}

if (async)

await reader.NextResultAsync();

else

reader.NextResult();

LoadCompositeFields(reader, byOID);

if (SupportsEnumTypes)

{

if (async)

await reader.NextResultAsync();

else

reader.NextResult();

LoadEnumLabels(reader, byOID);

}

return byOID.Values.ToList();

}

/// <summary>

/// Loads composite fields for the composite type specified by the OID.

/// </summary>

/// <param name="reader">The reader from which to read composite fields.</param>

/// <param name="byOID">The OID of the composite type for which fields are read.</param>

static void LoadCompositeFields(NpgsqlDataReader reader, Dictionary<uint, PostgresType> byOID)

{

var currentOID = uint.MaxValue;

PostgresCompositeType? currentComposite = null;

var skipCurrent = false;

while (reader.Read())

{

var oid = uint.Parse(reader.GetString("oid"), NumberFormatInfo.InvariantInfo);

if (oid != currentOID)

{

currentOID = oid;

if (!byOID.TryGetValue(oid, out var type)) // See #2020

{

Log.Warn($"Skipping composite type with OID {oid} which was not found in pg_type");

byOID.Remove(oid);

skipCurrent = true;

continue;

}

currentComposite = type as PostgresCompositeType;

if (currentComposite == null)

{

Log.Warn($"Type {type.Name} was referenced as a composite type but is a {type.GetType()}");

byOID.Remove(oid);

skipCurrent = true;

continue;

}

skipCurrent = false;

}

if (skipCurrent)

continue;

var fieldName = reader.GetString("attname");

var fieldTypeOID = uint.Parse(reader.GetString("atttypid"), NumberFormatInfo.InvariantInfo);

if (!byOID.TryGetValue(fieldTypeOID, out var fieldType)) // See #2020

{

Log.Warn($"Skipping composite type {currentComposite!.DisplayName} with field {fieldName} with type OID {fieldTypeOID}, which could not be resolved to a PostgreSQL type.");

byOID.Remove(oid);

skipCurrent = true;

continue;

}

currentComposite!.MutableFields.Add(new PostgresCompositeType.Field(fieldName, fieldType));

}

}

/// <summary>

/// Loads enum labels for the enum type specified by the OID.

/// </summary>

/// <param name="reader">The reader from which to read enum labels.</param>

/// <param name="byOID">The OID of the enum type for which labels are read.</param>

static void LoadEnumLabels(NpgsqlDataReader reader, Dictionary<uint, PostgresType> byOID)

{

var currentOID = uint.MaxValue;

PostgresEnumType? currentEnum = null;

var skipCurrent = false;

while (reader.Read())

{

var oid = uint.Parse(reader.GetString("oid"), NumberFormatInfo.InvariantInfo);

if (oid != currentOID)

{

currentOID = oid;

if (!byOID.TryGetValue(oid, out var type)) // See #2020

{

Log.Warn($"Skipping enum type with OID {oid} which was not found in pg_type");

byOID.Remove(oid);

skipCurrent = true;

continue;

}

currentEnum = type as PostgresEnumType;

if (currentEnum == null)

{

Log.Warn($"Type {type.Name} was referenced as an enum type but is a {type.GetType()}");

byOID.Remove(oid);

skipCurrent = true;

continue;

}

skipCurrent = false;

}

if (skipCurrent)

continue;

currentEnum!.MutableLabels.Add(reader.GetString("enumlabel"));

}

}

}