forked from npgsql/npgsql
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathNpgsqlRange.cs
More file actions
530 lines (439 loc) · 21.9 KB
/
NpgsqlRange.cs
File metadata and controls
530 lines (439 loc) · 21.9 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
using System;
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Text;
// ReSharper disable once CheckNamespace
namespace NpgsqlTypes;
/// <summary>
/// Represents a PostgreSQL range type.
/// </summary>
/// <typeparam name="T">The element type of the values in the range.</typeparam>
/// <remarks>
/// See: https://www.postgresql.org/docs/current/static/rangetypes.html
/// </remarks>
public readonly struct NpgsqlRange<T> : IEquatable<NpgsqlRange<T>>
{
// -----------------------------------------------------------------------------------------------
// Regarding bitwise flag checks via @roji:
//
// > Note that Flags.HasFlag() used to be very inefficient compared to simply doing the
// > bit operation - this is why I've always avoided it. .NET Core 2.1 adds JIT intrinstics
// > for this, making Enum.HasFlag() fast, but I honestly don't see the value over just doing
// > a bitwise and operation, which would also be fast under .NET Core 2.0 and .NET Framework.
//
// See:
// - https://github.com/npgsql/npgsql/pull/1939#pullrequestreview-121308396
// - https://blogs.msdn.microsoft.com/dotnet/2018/04/18/performance-improvements-in-net-core-2-1
// -----------------------------------------------------------------------------------------------
/// <summary>
/// Defined by PostgreSQL to represent an empty range.
/// </summary>
const string EmptyLiteral = "empty";
/// <summary>
/// Defined by PostgreSQL to represent an infinite lower bound.
/// Some element types may have specific handling for this value distinct from a missing or null value.
/// </summary>
const string LowerInfinityLiteral = "-infinity";
/// <summary>
/// Defined by PostgreSQL to represent an infinite upper bound.
/// Some element types may have specific handling for this value distinct from a missing or null value.
/// </summary>
const string UpperInfinityLiteral = "infinity";
/// <summary>
/// Defined by PostgreSQL to represent an null bound.
/// Some element types may have specific handling for this value distinct from an infinite or missing value.
/// </summary>
const string NullLiteral = "null";
/// <summary>
/// Defined by PostgreSQL to represent a lower inclusive bound.
/// </summary>
const char LowerInclusiveBound = '[';
/// <summary>
/// Defined by PostgreSQL to represent a lower exclusive bound.
/// </summary>
const char LowerExclusiveBound = '(';
/// <summary>
/// Defined by PostgreSQL to represent an upper inclusive bound.
/// </summary>
const char UpperInclusiveBound = ']';
/// <summary>
/// Defined by PostgreSQL to represent an upper exclusive bound.
/// </summary>
const char UpperExclusiveBound = ')';
/// <summary>
/// Defined by PostgreSQL to separate the values for the upper and lower bounds.
/// </summary>
const char BoundSeparator = ',';
/// <summary>
/// The <see cref="TypeConverter"/> used by <see cref="Parse"/> to convert <see cref="string"/> bounds into <typeparamref name="T"/>.
/// </summary>
static TypeConverter? BoundConverter;
/// <summary>
/// True if <typeparamref name="T"/> implements <see cref="IEquatable{T}"/>; otherwise, false.
/// </summary>
static readonly bool HasEquatableBounds = typeof(IEquatable<T>).IsAssignableFrom(typeof(T));
/// <summary>
/// Represents the empty range. This field is read-only.
/// </summary>
public static readonly NpgsqlRange<T> Empty = new(default, default, RangeFlags.Empty);
/// <summary>
/// The lower bound of the range. Only valid when <see cref="LowerBoundInfinite"/> is false.
/// </summary>
[MaybeNull, AllowNull]
public T LowerBound { get; }
/// <summary>
/// The upper bound of the range. Only valid when <see cref="UpperBoundInfinite"/> is false.
/// </summary>
[MaybeNull, AllowNull]
public T UpperBound { get; }
/// <summary>
/// The characteristics of the boundaries.
/// </summary>
internal readonly RangeFlags Flags;
/// <summary>
/// True if the lower bound is part of the range (i.e. inclusive); otherwise, false.
/// </summary>
public bool LowerBoundIsInclusive => (Flags & RangeFlags.LowerBoundInclusive) != 0;
/// <summary>
/// True if the upper bound is part of the range (i.e. inclusive); otherwise, false.
/// </summary>
public bool UpperBoundIsInclusive => (Flags & RangeFlags.UpperBoundInclusive) != 0;
/// <summary>
/// True if the lower bound is indefinite (i.e. infinite or unbounded); otherwise, false.
/// </summary>
public bool LowerBoundInfinite => (Flags & RangeFlags.LowerBoundInfinite) != 0;
/// <summary>
/// True if the upper bound is indefinite (i.e. infinite or unbounded); otherwise, false.
/// </summary>
public bool UpperBoundInfinite => (Flags & RangeFlags.UpperBoundInfinite) != 0;
/// <summary>
/// True if the range is empty; otherwise, false.
/// </summary>
public bool IsEmpty => (Flags & RangeFlags.Empty) != 0;
/// <summary>
/// Constructs an <see cref="NpgsqlRange{T}"/> with inclusive and definite bounds.
/// </summary>
/// <param name="lowerBound">The lower bound of the range.</param>
/// <param name="upperBound">The upper bound of the range.</param>
public NpgsqlRange([AllowNull] T lowerBound, [AllowNull] T upperBound)
: this(lowerBound, true, false, upperBound, true, false) { }
/// <summary>
/// Constructs an <see cref="NpgsqlRange{T}"/> with definite bounds.
/// </summary>
/// <param name="lowerBound">The lower bound of the range.</param>
/// <param name="lowerBoundIsInclusive">True if the lower bound is is part of the range (i.e. inclusive); otherwise, false.</param>
/// <param name="upperBound">The upper bound of the range.</param>
/// <param name="upperBoundIsInclusive">True if the upper bound is part of the range (i.e. inclusive); otherwise, false.</param>
public NpgsqlRange(
[AllowNull] T lowerBound, bool lowerBoundIsInclusive,
[AllowNull] T upperBound, bool upperBoundIsInclusive)
: this(lowerBound, lowerBoundIsInclusive, false, upperBound, upperBoundIsInclusive, false) { }
/// <summary>
/// Constructs an <see cref="NpgsqlRange{T}"/>.
/// </summary>
/// <param name="lowerBound">The lower bound of the range.</param>
/// <param name="lowerBoundIsInclusive">True if the lower bound is is part of the range (i.e. inclusive); otherwise, false.</param>
/// <param name="lowerBoundInfinite">True if the lower bound is indefinite (i.e. infinite or unbounded); otherwise, false.</param>
/// <param name="upperBound">The upper bound of the range.</param>
/// <param name="upperBoundIsInclusive">True if the upper bound is part of the range (i.e. inclusive); otherwise, false.</param>
/// <param name="upperBoundInfinite">True if the upper bound is indefinite (i.e. infinite or unbounded); otherwise, false.</param>
public NpgsqlRange(
[AllowNull] T lowerBound, bool lowerBoundIsInclusive, bool lowerBoundInfinite,
[AllowNull] T upperBound, bool upperBoundIsInclusive, bool upperBoundInfinite)
: this(
lowerBound,
upperBound,
EvaluateBoundaryFlags(
lowerBoundIsInclusive,
upperBoundIsInclusive,
lowerBoundInfinite,
upperBoundInfinite)) { }
/// <summary>
/// Constructs an <see cref="NpgsqlRange{T}"/>.
/// </summary>
/// <param name="lowerBound">The lower bound of the range.</param>
/// <param name="upperBound">The upper bound of the range.</param>
/// <param name="flags">The characteristics of the range boundaries.</param>
internal NpgsqlRange([AllowNull] T lowerBound, [AllowNull] T upperBound, RangeFlags flags) : this()
{
// TODO: We need to check if the bounds are implicitly empty. E.g. '(1,1)' or '(0,0]'.
// See: https://github.com/npgsql/npgsql/issues/1943.
LowerBound = (flags & RangeFlags.LowerBoundInfinite) != 0 ? default : lowerBound;
UpperBound = (flags & RangeFlags.UpperBoundInfinite) != 0 ? default : upperBound;
Flags = flags;
if (IsEmptyRange(LowerBound, UpperBound, Flags))
{
LowerBound = default!;
UpperBound = default!;
Flags = RangeFlags.Empty;
}
}
/// <summary>
/// Attempts to determine if the range is malformed or implicitly empty.
/// </summary>
/// <param name="lowerBound">The lower bound of the range.</param>
/// <param name="upperBound">The upper bound of the range.</param>
/// <param name="flags">The characteristics of the range boundaries.</param>
/// <returns>
/// True if the range is implicitly empty; otherwise, false.
/// </returns>
static bool IsEmptyRange([AllowNull] T lowerBound, [AllowNull] T upperBound, RangeFlags flags)
{
// ---------------------------------------------------------------------------------
// We only want to check for those conditions that are unambiguously erroneous:
// 1. The bounds must not be default values (including null).
// 2. The bounds must be definite (non-infinite).
// 3. The bounds must be inclusive.
// 4. The bounds must be considered equal.
//
// See:
// - https://github.com/npgsql/npgsql/pull/1939
// - https://github.com/npgsql/npgsql/issues/1943
// ---------------------------------------------------------------------------------
if ((flags & RangeFlags.Empty) == RangeFlags.Empty)
return true;
if ((flags & RangeFlags.Infinite) == RangeFlags.Infinite)
return false;
if ((flags & RangeFlags.Inclusive) == RangeFlags.Inclusive)
return false;
if (lowerBound is null || upperBound is null)
return false;
if (!HasEquatableBounds)
return lowerBound?.Equals(upperBound) ?? false;
var lower = (IEquatable<T>)lowerBound;
var upper = (IEquatable<T>)upperBound;
return !lower.Equals(default!) && !upper.Equals(default!) && lower.Equals(upperBound);
}
/// <summary>
/// Evaluates the boundary flags.
/// </summary>
/// <param name="lowerBoundIsInclusive">True if the lower bound is is part of the range (i.e. inclusive); otherwise, false.</param>
/// <param name="lowerBoundInfinite">True if the lower bound is indefinite (i.e. infinite or unbounded); otherwise, false.</param>
/// <param name="upperBoundIsInclusive">True if the upper bound is part of the range (i.e. inclusive); otherwise, false.</param>
/// <param name="upperBoundInfinite">True if the upper bound is indefinite (i.e. infinite or unbounded); otherwise, false.</param>
/// <returns>
/// The boundary characteristics.
/// </returns>
static RangeFlags EvaluateBoundaryFlags(bool lowerBoundIsInclusive, bool upperBoundIsInclusive, bool lowerBoundInfinite, bool upperBoundInfinite)
{
var result = RangeFlags.None;
// This is the only place flags are calculated.
if (lowerBoundIsInclusive)
result |= RangeFlags.LowerBoundInclusive;
if (upperBoundIsInclusive)
result |= RangeFlags.UpperBoundInclusive;
if (lowerBoundInfinite)
result |= RangeFlags.LowerBoundInfinite;
if (upperBoundInfinite)
result |= RangeFlags.UpperBoundInfinite;
// PostgreSQL automatically converts inclusive-infinities.
// See: https://www.postgresql.org/docs/current/static/rangetypes.html#RANGETYPES-INFINITE
if ((result & RangeFlags.LowerInclusiveInfinite) == RangeFlags.LowerInclusiveInfinite)
result &= ~RangeFlags.LowerBoundInclusive;
if ((result & RangeFlags.UpperInclusiveInfinite) == RangeFlags.UpperInclusiveInfinite)
result &= ~RangeFlags.UpperBoundInclusive;
return result;
}
/// <summary>
/// Indicates whether the <see cref="NpgsqlRange{T}"/> on the left is equal to the <see cref="NpgsqlRange{T}"/> on the right.
/// </summary>
/// <param name="x">The <see cref="NpgsqlRange{T}"/> on the left.</param>
/// <param name="y">The <see cref="NpgsqlRange{T}"/> on the right.</param>
/// <returns>
/// True if the <see cref="NpgsqlRange{T}"/> on the left is equal to the <see cref="NpgsqlRange{T}"/> on the right; otherwise, false.
/// </returns>
public static bool operator ==(NpgsqlRange<T> x, NpgsqlRange<T> y) => x.Equals(y);
/// <summary>
/// Indicates whether the <see cref="NpgsqlRange{T}"/> on the left is not equal to the <see cref="NpgsqlRange{T}"/> on the right.
/// </summary>
/// <param name="x">The <see cref="NpgsqlRange{T}"/> on the left.</param>
/// <param name="y">The <see cref="NpgsqlRange{T}"/> on the right.</param>
/// <returns>
/// True if the <see cref="NpgsqlRange{T}"/> on the left is not equal to the <see cref="NpgsqlRange{T}"/> on the right; otherwise, false.
/// </returns>
public static bool operator !=(NpgsqlRange<T> x, NpgsqlRange<T> y) => !x.Equals(y);
/// <inheritdoc />
public override bool Equals(object? o) => o is NpgsqlRange<T> range && Equals(range);
/// <inheritdoc />
public bool Equals(NpgsqlRange<T> other)
{
if (Flags != other.Flags)
return false;
if (HasEquatableBounds)
{
var lowerEqual = LowerBound is null
? other.LowerBound is null
: !(other.LowerBound is null) && ((IEquatable<T>)LowerBound).Equals(other.LowerBound);
if (!lowerEqual)
return false;
return UpperBound is null
? other.UpperBound is null
: !(other.UpperBound is null) && ((IEquatable<T>)UpperBound).Equals(other.UpperBound);
}
return
(LowerBound?.Equals(other.LowerBound) ?? other.LowerBound is null) &&
(UpperBound?.Equals(other.UpperBound) ?? other.UpperBound is null);
}
/// <inheritdoc />
public override int GetHashCode()
=> unchecked((397 * (int)Flags) ^ (397 * (LowerBound?.GetHashCode() ?? 0)) ^ (397 * (UpperBound?.GetHashCode() ?? 0)));
/// <inheritdoc />
public override string ToString()
{
if (IsEmpty)
return EmptyLiteral;
var sb = new StringBuilder();
sb.Append(LowerBoundIsInclusive ? LowerInclusiveBound : LowerExclusiveBound);
if (!LowerBoundInfinite)
sb.Append(LowerBound);
sb.Append(BoundSeparator);
if (!UpperBoundInfinite)
sb.Append(UpperBound);
sb.Append(UpperBoundIsInclusive ? UpperInclusiveBound : UpperExclusiveBound);
return sb.ToString();
}
// TODO: rewrite this to use ReadOnlySpan<char> for the 4.1 release
/// <summary>
/// Parses the well-known text representation of a PostgreSQL range type into a <see cref="NpgsqlRange{T}"/>.
/// </summary>
/// <param name="value">A PosgreSQL range type in a well-known text format.</param>
/// <returns>
/// The <see cref="NpgsqlRange{T}"/> represented by the <paramref name="value"/>.
/// </returns>
/// <exception cref="FormatException">
/// Malformed range literal.
/// </exception>
/// <exception cref="FormatException">
/// Malformed range literal. Missing left parenthesis or bracket.
/// </exception>
/// <exception cref="FormatException">
/// Malformed range literal. Missing right parenthesis or bracket.
/// </exception>
/// <exception cref="FormatException">
/// Malformed range literal. Missing comma after lower bound.
/// </exception>
/// <remarks>
/// See: https://www.postgresql.org/docs/current/static/rangetypes.html
/// </remarks>
[RequiresUnreferencedCode("Parse implementations for certain types of T may require members that have been trimmed.")]
public static NpgsqlRange<T> Parse(string value)
{
if (value is null)
throw new ArgumentNullException(nameof(value));
value = value.Trim();
if (value.Length < 3)
throw new FormatException("Malformed range literal.");
if (string.Equals(value, EmptyLiteral, StringComparison.OrdinalIgnoreCase))
return Empty;
var lowerInclusive = value[0] == LowerInclusiveBound;
var lowerExclusive = value[0] == LowerExclusiveBound;
if (!lowerInclusive && !lowerExclusive)
throw new FormatException("Malformed range literal. Missing left parenthesis or bracket.");
var upperInclusive = value[value.Length - 1] == UpperInclusiveBound;
var upperExclusive = value[value.Length - 1] == UpperExclusiveBound;
if (!upperInclusive && !upperExclusive)
throw new FormatException("Malformed range literal. Missing right parenthesis or bracket.");
var separator = value.IndexOf(BoundSeparator);
if (separator == -1)
throw new FormatException("Malformed range literal. Missing comma after lower bound.");
if (separator != value.LastIndexOf(BoundSeparator))
// TODO: this should be replaced to handle quoted commas.
throw new NotSupportedException("Ranges with embedded commas are not currently supported.");
// Skip the opening bracket and stop short of the separator.
var lowerSegment = value.Substring(1, separator - 1).Trim();
// Skip past the separator and stop short of the closing bracket.
var upperSegment = value.Substring(separator + 1, value.Length - separator - 2).Trim();
// TODO: infinity literals have special meaning to some types (e.g. daterange), we should consider a flag to track them.
var lowerInfinite =
lowerSegment.Length == 0 ||
string.Equals(lowerSegment, string.Empty, StringComparison.OrdinalIgnoreCase) ||
string.Equals(lowerSegment, NullLiteral, StringComparison.OrdinalIgnoreCase) ||
string.Equals(lowerSegment, LowerInfinityLiteral, StringComparison.OrdinalIgnoreCase);
var upperInfinite =
upperSegment.Length == 0 ||
string.Equals(upperSegment, string.Empty, StringComparison.OrdinalIgnoreCase) ||
string.Equals(upperSegment, NullLiteral, StringComparison.OrdinalIgnoreCase) ||
string.Equals(upperSegment, UpperInfinityLiteral, StringComparison.OrdinalIgnoreCase);
BoundConverter ??= TypeDescriptor.GetConverter(typeof(T));
var lower = lowerInfinite ? default : (T?)BoundConverter.ConvertFromString(lowerSegment);
var upper = upperInfinite ? default : (T?)BoundConverter.ConvertFromString(upperSegment);
return new NpgsqlRange<T>(lower, lowerInclusive, lowerInfinite, upper, upperInclusive, upperInfinite);
}
/// <summary>
/// Represents a type converter for <see cref="NpgsqlRange{T}" />.
/// </summary>
[RequiresUnreferencedCode("ConvertFrom implementations for certain types of T may require members that have been trimmed.")]
public class RangeTypeConverter : TypeConverter
{
/// <summary>
/// Adds a <see cref="TypeConverterAttribute"/> to the closed form <see cref="NpgsqlRange{T}"/>.
/// </summary>
public static void Register() =>
TypeDescriptor.AddAttributes(
typeof(NpgsqlRange<T>),
new TypeConverterAttribute(typeof(RangeTypeConverter)));
/// <inheritdoc />
public override bool CanConvertFrom(ITypeDescriptorContext? context, Type sourceType)
=> sourceType == typeof(string);
/// <inheritdoc />
public override bool CanConvertTo(ITypeDescriptorContext? context, Type? destinationType)
=> destinationType == typeof(string);
/// <inheritdoc />
public override object? ConvertFrom(ITypeDescriptorContext? context, CultureInfo? culture, object value)
=> value is string s ? Parse(s) : base.ConvertFrom(context, culture, value);
/// <inheritdoc />
public override object? ConvertTo(ITypeDescriptorContext? context, CultureInfo? culture, object? value, Type destinationType)
=> value is null ? string.Empty : value.ToString();
}
}
/// <summary>
/// Represents characteristics of range type boundaries.
/// </summary>
/// <remarks>
/// See: https://www.postgresql.org/docs/current/static/rangetypes.html
/// </remarks>
[Flags]
enum RangeFlags : byte
{
/// <summary>
/// The default flag. The range is not empty and has boundaries that are definite and exclusive.
/// </summary>
None = 0,
/// <summary>
/// The range is empty. E.g. '(0,0)', 'empty'.
/// </summary>
Empty = 1,
/// <summary>
/// The lower bound is inclusive. E.g. '[0,5]', '[0,5)', '[0,)'.
/// </summary>
LowerBoundInclusive = 2,
/// <summary>
/// The upper bound is inclusive. E.g. '[0,5]', '(0,5]', '(,5]'.
/// </summary>
UpperBoundInclusive = 4,
/// <summary>
/// The lower bound is infinite or indefinite. E.g. '(null,5]', '(-infinity,5]', '(,5]'.
/// </summary>
LowerBoundInfinite = 8,
/// <summary>
/// The upper bound is infinite or indefinite. E.g. '[0,null)', '[0,infinity)', '[0,)'.
/// </summary>
UpperBoundInfinite = 16,
/// <summary>
/// Both the lower and upper bounds are inclusive.
/// </summary>
Inclusive = LowerBoundInclusive | UpperBoundInclusive,
/// <summary>
/// Both the lower and upper bounds are indefinite.
/// </summary>
Infinite = LowerBoundInfinite | UpperBoundInfinite,
/// <summary>
/// The lower bound is both inclusive and indefinite. This represents an error condition.
/// </summary>
LowerInclusiveInfinite = LowerBoundInclusive | LowerBoundInfinite,
/// <summary>
/// The upper bound is both inclusive and indefinite. This represents an error condition.
/// </summary>
UpperInclusiveInfinite = UpperBoundInclusive | UpperBoundInfinite
}