/// <summary>Create a range that will return all keys starting with <paramref name="prefix"/>: ('prefix' <= k < strinc('prefix'))</summary>
/// <param name="prefix"></param>
/// <returns></returns>
public static FdbKeyRange StartsWith(Slice prefix)
{
if (prefix.IsNull)
{
throw Fdb.Errors.KeyCannotBeNull("prefix");
}
// prefix => [ prefix, prefix + 1 )
return(new FdbKeyRange(
prefix,
FdbKey.Increment(prefix)
));
}
/// <summary>Create a range that selects all keys starting with <paramref name="prefix"/>, but not the prefix itself: ('prefix\x00' <= k < string('prefix')</summary>
/// <param name="prefix">Key prefix (that will be excluded from the range)</param>
/// <returns>Range including all keys with the specified prefix.</returns>
public static FdbKeyRange PrefixedBy(Slice prefix)
{
if (prefix.IsNull)
{
throw Fdb.Errors.KeyCannotBeNull("prefix");
}
// prefix => [ prefix."\0", prefix + 1)
return(new FdbKeyRange(
prefix + FdbKey.MinValue,
FdbKey.Increment(prefix)
));
}
/// <summary>Checks that a key is valid, and is inside the global key space of this database</summary>
/// <param name="database"></param>
/// <param name="key">Key to verify</param>
/// <param name="endExclusive">If true, the key is allowed to be one past the maximum key allowed by the global namespace</param>
/// <param name="ignoreError"></param>
/// <param name="error"></param>
/// <returns>An exception if the key is outside of the allowed key space of this database</returns>
internal static bool ValidateKey(IFdbDatabase database, ref Slice key, bool endExclusive, bool ignoreError, out Exception error)
{
error = null;
// null or empty keys are not allowed
if (key.IsNull)
{
if (!ignoreError)
{
error = Fdb.Errors.KeyCannotBeNull();
}
return(false);
}
// key cannot be larger than maximum allowed key size
if (key.Count > Fdb.MaxKeySize)
{
if (!ignoreError)
{
error = Fdb.Errors.KeyIsTooBig(key);
}
return(false);
}
// special case for system keys
if (IsSystemKey(ref key))
{
// note: it will fail later if the transaction does not have access to the system keys!
return(true);
}
// first, it MUST start with the root prefix of this database (if any)
if (!database.Contains(key))
{
// special case: if endExclusive is true (we are validating the end key of a ClearRange),
// and the key is EXACTLY equal to strinc(globalSpace.Prefix), we let is slide
if (!endExclusive ||
!key.Equals(FdbKey.Increment(database.GlobalSpace.GetPrefix()))) //TODO: cache this?
{
if (!ignoreError)
{
error = Fdb.Errors.InvalidKeyOutsideDatabaseNamespace(database, key);
}
return(false);
}
}
return(true);
}
/// <summary>Create a range that will return all keys starting with <paramref name="prefix"/>: ('prefix' <= k < strinc('prefix'))</summary>
/// <param name="prefix"></param>
/// <returns></returns>
public static KeyRange StartsWith(Slice prefix)
{
if (prefix.IsNull)
{
throw Fdb.Errors.KeyCannotBeNull("prefix");
}
if (prefix.Count == 0)
{
return(new KeyRange(Slice.Empty, FdbKey.MaxValue));
}
// prefix => [ prefix, prefix + 1 )
return(new KeyRange(
prefix,
FdbKey.Increment(prefix)
));
}
