68 lines
2.1 KiB
C
68 lines
2.1 KiB
C
/*
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* Copyright (c) 2011, Google Inc.
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*/
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#ifndef STREAMING_H
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#define STREAMING_H 1
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#include "object.h"
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struct object_database;
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struct odb_read_stream;
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struct stream_filter;
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typedef int (*odb_read_stream_close_fn)(struct odb_read_stream *);
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typedef ssize_t (*odb_read_stream_read_fn)(struct odb_read_stream *, char *, size_t);
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/*
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* A stream that can be used to read an object from the object database without
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* loading all of it into memory.
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*/
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struct odb_read_stream {
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odb_read_stream_close_fn close;
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odb_read_stream_read_fn read;
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enum object_type type;
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unsigned long size; /* inflated size of full object */
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};
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/*
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* Create a new object stream for the given object database. An optional filter
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* can be used to transform the object's content.
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*
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* Returns the stream on success, a `NULL` pointer otherwise.
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*/
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struct odb_read_stream *odb_read_stream_open(struct object_database *odb,
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const struct object_id *oid,
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struct stream_filter *filter);
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/*
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* Close the given read stream and release all resources associated with it.
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* Returns 0 on success, a negative error code otherwise.
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*/
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int odb_read_stream_close(struct odb_read_stream *stream);
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/*
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* Read data from the stream into the buffer. Returns 0 on EOF and the number
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* of bytes read on success. Returns a negative error code in case reading from
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* the stream fails.
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*/
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ssize_t odb_read_stream_read(struct odb_read_stream *stream, void *buf, size_t len);
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/*
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* Look up the object by its ID and write the full contents to the file
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* descriptor. The object must be a blob, or the function will fail. When
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* provided, the filter is used to transform the blob contents.
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*
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* `can_seek` should be set to 1 in case the given file descriptor can be
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* seek(3p)'d on. This is used to support files with holes in case a
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* significant portion of the blob contains NUL bytes.
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*
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* Returns a negative error code on failure, 0 on success.
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*/
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int odb_stream_blob_to_fd(struct object_database *odb,
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int fd,
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const struct object_id *oid,
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struct stream_filter *filter,
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int can_seek);
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#endif /* STREAMING_H */
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