51 lines
1.5 KiB
Go
51 lines
1.5 KiB
Go
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/*
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* Minio Cloud Storage, (C) 2016 Minio, Inc.
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*
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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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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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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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*/
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// Package objcache implements in memory caching methods.
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package objcache
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// Used for adding entry to the object cache.
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// Implements io.WriteCloser
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type cappedWriter struct {
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offset int64
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cap int64
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buffer []byte
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onClose func() error
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}
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// Write implements a limited writer, returns error.
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// if the writes go beyond allocated size.
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func (c *cappedWriter) Write(b []byte) (n int, err error) {
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if c.offset+int64(len(b)) > c.cap {
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return 0, ErrExcessData
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}
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n = copy(c.buffer[int(c.offset):int(c.offset)+len(b)], b)
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c.offset = c.offset + int64(n)
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return n, nil
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}
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// Reset relinquishes the allocated underlying buffer.
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func (c *cappedWriter) Reset() {
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c.buffer = nil
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}
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// On close, onClose() is called which checks if all object contents
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// have been written so that it can save the buffer to the cache.
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func (c cappedWriter) Close() (err error) {
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return c.onClose()
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}
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