| 1 | /*
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| 2 | Copyright (C) 2015 Yusuke Suzuki <utatane.tea@gmail.com>
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| 3 |
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| 4 | Redistribution and use in source and binary forms, with or without
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| 5 | modification, are permitted provided that the following conditions are met:
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| 6 |
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| 7 | * Redistributions of source code must retain the above copyright
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| 8 | notice, this list of conditions and the following disclaimer.
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| 9 | * Redistributions in binary form must reproduce the above copyright
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| 10 | notice, this list of conditions and the following disclaimer in the
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| 11 | documentation and/or other materials provided with the distribution.
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| 12 |
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| 13 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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| 14 | AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 15 | IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 16 | ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
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| 17 | DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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| 18 | (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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| 19 | LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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| 20 | ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 21 | (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 22 | THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 23 | */
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| 24 |
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| 25 | const READ = 0x1;
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| 26 | const WRITE = 0x2;
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| 27 | const RW = READ | WRITE;
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| 28 |
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| 29 | /**
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| 30 | * A Reference represents a single occurrence of an identifier in code.
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| 31 | * @constructor Reference
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| 32 | */
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| 33 | class Reference {
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| 34 | constructor(ident, scope, flag, writeExpr, maybeImplicitGlobal, partial, init) {
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| 35 |
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| 36 | /**
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| 37 | * Identifier syntax node.
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| 38 | * @member {espreeIdentifier} Reference#identifier
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| 39 | */
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| 40 | this.identifier = ident;
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| 41 |
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| 42 | /**
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| 43 | * Reference to the enclosing Scope.
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| 44 | * @member {Scope} Reference#from
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| 45 | */
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| 46 | this.from = scope;
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| 47 |
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| 48 | /**
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| 49 | * Whether the reference comes from a dynamic scope (such as 'eval',
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| 50 | * 'with', etc.), and may be trapped by dynamic scopes.
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| 51 | * @member {boolean} Reference#tainted
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| 52 | */
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| 53 | this.tainted = false;
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| 54 |
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| 55 | /**
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| 56 | * The variable this reference is resolved with.
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| 57 | * @member {Variable} Reference#resolved
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| 58 | */
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| 59 | this.resolved = null;
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| 60 |
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| 61 | /**
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| 62 | * The read-write mode of the reference. (Value is one of {@link
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| 63 | * Reference.READ}, {@link Reference.RW}, {@link Reference.WRITE}).
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| 64 | * @member {number} Reference#flag
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| 65 | * @private
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| 66 | */
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| 67 | this.flag = flag;
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| 68 | if (this.isWrite()) {
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| 69 |
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| 70 | /**
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| 71 | * If reference is writeable, this is the tree being written to it.
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| 72 | * @member {espreeNode} Reference#writeExpr
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| 73 | */
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| 74 | this.writeExpr = writeExpr;
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| 75 |
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| 76 | /**
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| 77 | * Whether the Reference might refer to a partial value of writeExpr.
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| 78 | * @member {boolean} Reference#partial
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| 79 | */
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| 80 | this.partial = partial;
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| 81 |
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| 82 | /**
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| 83 | * Whether the Reference is to write of initialization.
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| 84 | * @member {boolean} Reference#init
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| 85 | */
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| 86 | this.init = init;
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| 87 | }
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| 88 | this.__maybeImplicitGlobal = maybeImplicitGlobal;
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| 89 | }
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| 90 |
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| 91 | /**
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| 92 | * Whether the reference is static.
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| 93 | * @function Reference#isStatic
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| 94 | * @returns {boolean} static
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| 95 | */
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| 96 | isStatic() {
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| 97 | return !this.tainted && this.resolved && this.resolved.scope.isStatic();
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| 98 | }
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| 99 |
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| 100 | /**
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| 101 | * Whether the reference is writeable.
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| 102 | * @function Reference#isWrite
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| 103 | * @returns {boolean} write
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| 104 | */
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| 105 | isWrite() {
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| 106 | return !!(this.flag & Reference.WRITE);
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| 107 | }
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| 108 |
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| 109 | /**
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| 110 | * Whether the reference is readable.
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| 111 | * @function Reference#isRead
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| 112 | * @returns {boolean} read
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| 113 | */
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| 114 | isRead() {
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| 115 | return !!(this.flag & Reference.READ);
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| 116 | }
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| 117 |
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| 118 | /**
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| 119 | * Whether the reference is read-only.
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| 120 | * @function Reference#isReadOnly
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| 121 | * @returns {boolean} read only
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| 122 | */
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| 123 | isReadOnly() {
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| 124 | return this.flag === Reference.READ;
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| 125 | }
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| 126 |
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| 127 | /**
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| 128 | * Whether the reference is write-only.
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| 129 | * @function Reference#isWriteOnly
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| 130 | * @returns {boolean} write only
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| 131 | */
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| 132 | isWriteOnly() {
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| 133 | return this.flag === Reference.WRITE;
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| 134 | }
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| 135 |
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| 136 | /**
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| 137 | * Whether the reference is read-write.
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| 138 | * @function Reference#isReadWrite
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| 139 | * @returns {boolean} read write
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| 140 | */
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| 141 | isReadWrite() {
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| 142 | return this.flag === Reference.RW;
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| 143 | }
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| 144 | }
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| 145 |
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| 146 | /**
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| 147 | * @constant Reference.READ
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| 148 | * @private
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| 149 | */
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| 150 | Reference.READ = READ;
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| 151 |
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| 152 | /**
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| 153 | * @constant Reference.WRITE
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| 154 | * @private
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| 155 | */
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| 156 | Reference.WRITE = WRITE;
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| 157 |
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| 158 | /**
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| 159 | * @constant Reference.RW
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| 160 | * @private
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| 161 | */
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| 162 | Reference.RW = RW;
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| 163 |
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| 164 | export default Reference;
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| 165 |
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| 166 | /* vim: set sw=4 ts=4 et tw=80 : */
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