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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 // Routines used to validate and normalize arguments. | |
6 // TODO(benwells): unit test this file. | |
7 | |
8 var JSONSchemaValidator = require('json_schema').JSONSchemaValidator; | |
9 | |
10 var schemaValidator = new JSONSchemaValidator(); | |
11 | |
12 // Validate arguments. | |
13 function validate(args, parameterSchemas) { | |
14 if (args.length > parameterSchemas.length) | |
15 throw new Error("Too many arguments."); | |
16 for (var i = 0; i < parameterSchemas.length; i++) { | |
17 if (i in args && args[i] !== null && args[i] !== undefined) { | |
18 schemaValidator.resetErrors(); | |
19 schemaValidator.validate(args[i], parameterSchemas[i]); | |
20 if (schemaValidator.errors.length == 0) | |
21 continue; | |
22 var message = "Invalid value for argument " + (i + 1) + ". "; | |
23 for (var i = 0, err; | |
24 err = schemaValidator.errors[i]; i++) { | |
25 if (err.path) { | |
26 message += "Property '" + err.path + "': "; | |
27 } | |
28 message += err.message; | |
29 message = message.substring(0, message.length - 1); | |
30 message += ", "; | |
31 } | |
32 message = message.substring(0, message.length - 2); | |
33 message += "."; | |
34 throw new Error(message); | |
35 } else if (!parameterSchemas[i].optional) { | |
36 throw new Error("Parameter " + (i + 1) + " (" + | |
37 parameterSchemas[i].name + ") is required."); | |
38 } | |
39 } | |
40 } | |
41 | |
42 // Generate all possible signatures for a given API function. | |
43 function getSignatures(parameterSchemas) { | |
44 if (parameterSchemas.length === 0) | |
45 return [[]]; | |
46 var signatures = []; | |
47 var remaining = getSignatures($Array.slice(parameterSchemas, 1)); | |
48 for (var i = 0; i < remaining.length; i++) | |
49 $Array.push(signatures, $Array.concat([parameterSchemas[0]], remaining[i])) | |
50 if (parameterSchemas[0].optional) | |
51 return $Array.concat(signatures, remaining); | |
52 return signatures; | |
53 }; | |
54 | |
55 // Return true if arguments match a given signature's schema. | |
56 function argumentsMatchSignature(args, candidateSignature) { | |
57 if (args.length != candidateSignature.length) | |
58 return false; | |
59 for (var i = 0; i < candidateSignature.length; i++) { | |
60 var argType = JSONSchemaValidator.getType(args[i]); | |
61 if (!schemaValidator.isValidSchemaType(argType, | |
62 candidateSignature[i])) | |
63 return false; | |
64 } | |
65 return true; | |
66 }; | |
67 | |
68 // Finds the function signature for the given arguments. | |
69 function resolveSignature(args, definedSignature) { | |
70 var candidateSignatures = getSignatures(definedSignature); | |
71 for (var i = 0; i < candidateSignatures.length; i++) { | |
72 if (argumentsMatchSignature(args, candidateSignatures[i])) | |
73 return candidateSignatures[i]; | |
74 } | |
75 return null; | |
76 }; | |
77 | |
78 // Returns a string representing the defined signature of the API function. | |
79 // Example return value for chrome.windows.getCurrent: | |
80 // "windows.getCurrent(optional object populate, function callback)" | |
81 function getParameterSignatureString(name, definedSignature) { | |
82 var getSchemaTypeString = function(schema) { | |
83 var schemaTypes = schemaValidator.getAllTypesForSchema(schema); | |
84 var typeName = schemaTypes.join(" or ") + " " + schema.name; | |
85 if (schema.optional) | |
86 return "optional " + typeName; | |
87 return typeName; | |
88 }; | |
89 var typeNames = definedSignature.map(getSchemaTypeString); | |
90 return name + "(" + typeNames.join(", ") + ")"; | |
91 }; | |
92 | |
93 // Returns a string representing a call to an API function. | |
94 // Example return value for call: chrome.windows.get(1, callback) is: | |
95 // "windows.get(int, function)" | |
96 function getArgumentSignatureString(name, args) { | |
97 var typeNames = args.map(JSONSchemaValidator.getType); | |
98 return name + "(" + typeNames.join(", ") + ")"; | |
99 }; | |
100 | |
101 // Finds the correct signature for the given arguments, then validates the | |
102 // arguments against that signature. Returns a 'normalized' arguments list | |
103 // where nulls are inserted where optional parameters were omitted. | |
104 // |args| is expected to be an array. | |
105 function normalizeArgumentsAndValidate(args, funDef) { | |
106 if (funDef.allowAmbiguousOptionalArguments) { | |
107 validate(args, funDef.definition.parameters); | |
108 return args; | |
109 } | |
110 var definedSignature = funDef.definition.parameters; | |
111 var resolvedSignature = resolveSignature(args, definedSignature); | |
112 if (!resolvedSignature) | |
113 throw new Error("Invocation of form " + | |
114 getArgumentSignatureString(funDef.name, args) + | |
115 " doesn't match definition " + | |
116 getParameterSignatureString(funDef.name, definedSignature)); | |
117 validate(args, resolvedSignature); | |
118 var normalizedArgs = []; | |
119 var ai = 0; | |
120 for (var si = 0; si < definedSignature.length; si++) { | |
121 if (definedSignature[si] === resolvedSignature[ai]) | |
122 $Array.push(normalizedArgs, args[ai++]); | |
123 else | |
124 $Array.push(normalizedArgs, null); | |
125 } | |
126 return normalizedArgs; | |
127 }; | |
128 | |
129 // Validates that a given schema for an API function is not ambiguous. | |
130 function isFunctionSignatureAmbiguous(functionDef) { | |
131 if (functionDef.allowAmbiguousOptionalArguments) | |
132 return false; | |
133 var signaturesAmbiguous = function(signature1, signature2) { | |
134 if (signature1.length != signature2.length) | |
135 return false; | |
136 for (var i = 0; i < signature1.length; i++) { | |
137 if (!schemaValidator.checkSchemaOverlap( | |
138 signature1[i], signature2[i])) | |
139 return false; | |
140 } | |
141 return true; | |
142 }; | |
143 var candidateSignatures = getSignatures(functionDef.parameters); | |
144 for (var i = 0; i < candidateSignatures.length; i++) { | |
145 for (var j = i + 1; j < candidateSignatures.length; j++) { | |
146 if (signaturesAmbiguous(candidateSignatures[i], candidateSignatures[j])) | |
147 return true; | |
148 } | |
149 } | |
150 return false; | |
151 }; | |
152 | |
153 exports.isFunctionSignatureAmbiguous = isFunctionSignatureAmbiguous; | |
154 exports.normalizeArgumentsAndValidate = normalizeArgumentsAndValidate; | |
155 exports.schemaValidator = schemaValidator; | |
156 exports.validate = validate; | |
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