73 lines
1.9 KiB
JavaScript
73 lines
1.9 KiB
JavaScript
/*
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Copyright 2017 Google Inc.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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https://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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import {WorkboxError} from 'workbox-core/_private/WorkboxError.mjs';
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import {assert} from 'workbox-core/_private/assert.mjs';
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import '../_version.mjs';
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/**
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* @param {Blob} blob A source blob.
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* @param {number|null} start The offset to use as the start of the
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* slice.
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* @param {number|null} end The offset to use as the end of the slice.
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* @return {Object} An object with `start` and `end` properties, reflecting
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* the effective boundaries to use given the size of the blob.
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*
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* @private
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*/
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function calculateEffectiveBoundaries(blob, start, end) {
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if (process.env.NODE_ENV !== 'production') {
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assert.isInstance(blob, Blob, {
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moduleName: 'workbox-range-requests',
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funcName: 'calculateEffectiveBoundaries',
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paramName: 'blob',
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});
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}
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const blobSize = blob.size;
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if (end > blobSize || start < 0) {
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throw new WorkboxError('range-not-satisfiable', {
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size: blobSize,
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end,
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start,
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});
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}
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let effectiveStart;
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let effectiveEnd;
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if (start === null) {
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effectiveStart = blobSize - end;
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effectiveEnd = blobSize;
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} else if (end === null) {
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effectiveStart = start;
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effectiveEnd = blobSize;
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} else {
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effectiveStart = start;
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// Range values are inclusive, so add 1 to the value.
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effectiveEnd = end + 1;
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}
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return {
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start: effectiveStart,
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end: effectiveEnd,
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};
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}
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export {calculateEffectiveBoundaries};
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