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
|
// Copyright 2017 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.devtools.build.lib.packages;
import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
import com.google.devtools.build.lib.events.Location;
import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
import com.google.devtools.build.lib.syntax.BaseFunction;
import com.google.devtools.build.lib.syntax.Environment;
import com.google.devtools.build.lib.syntax.EvalException;
import com.google.devtools.build.lib.syntax.FuncallExpression;
import com.google.devtools.build.lib.syntax.FunctionSignature;
import com.google.devtools.build.lib.syntax.SkylarkType;
import javax.annotation.Nullable;
/**
* Declared Provider (a constructor for {@link SkylarkClassObject}).
*
* Declared providers can be declared either natively ({@link NativeClassObjectConstructor}
* or in Skylark {@link SkylarkClassObjectConstructor}.
*
* {@link ClassObjectConstructor} serves both as "type identifier" for declared provider
* instances and as a function that can be called to construct a provider.
*
* Prefer to use {@link Key} as a serializable identifier of {@link ClassObjectConstructor}.
* In particular, {@link Key} should be used in all data structures exposed to Skyframe.
*/
@SkylarkModule(name = "provider",
doc = "A constructor for simple value objects. "
+ "See the global <a href=\"globals.html#provider\">provider</a> function "
+ "for more details."
)
@Immutable
public abstract class ClassObjectConstructor extends BaseFunction {
protected ClassObjectConstructor(String name,
FunctionSignature.WithValues<Object, SkylarkType> signature,
Location location) {
super(name, signature, location);
}
/**
* Has this {@link ClassObjectConstructor} been exported?
* All native constructors are always exported. Skylark constructors are exported
* if they are assigned to top-level name in a Skylark module.
*/
public abstract boolean isExported();
/**
* Returns a serializable representation of this constructor.
*/
public abstract Key getKey();
/**
* Returns a name of this constructor that should be used in error messages.
*/
public abstract String getPrintableName();
/**
* Returns an error message format for instances.
*
* Must contain one '%s' placeholder for field name.
*/
public abstract String getErrorMessageFormatForInstances();
@Override
protected Object call(Object[] args, @Nullable FuncallExpression ast, @Nullable Environment env)
throws EvalException, InterruptedException {
Location loc = ast != null ? ast.getLocation() : Location.BUILTIN;
return createInstanceFromSkylark(args, loc);
}
/**
* Override this method to provide logic that is used to instantiate a declared provider
* from Skylark.
*
* This is a method that is called when a constructor {@code c} is invoked as<br>
* {@code c(arg1 = val1, arg2 = val2, ...)}.
*
* @param args an array of argument values sorted as per the signature
* ({@see BaseFunction#call})
*/
protected abstract SkylarkClassObject createInstanceFromSkylark(Object[] args, Location loc)
throws EvalException;
/**
* A serializable representation of {@link ClassObjectConstructor}.
*/
// todo(vladmos,dslomov): when we allow declared providers in `requiredProviders`,
// we will need to serialize this somehow.
public abstract static class Key {}
}
|
