branchcache: skip entries that are topological heads in the on disk file In the majority of cases, topological heads are also branch heads. We have efficient way to get the topological heads and efficient way to retrieve their branch information. So there is little value in putting them in the branch cache file explicitly. On the contrary, writing them explicitly tend to create very large cache file that are inefficient to read and update. So the branch cache v3 format is no longer including them. This changeset focus on the format aspect and have no focus on the performance aspect. We will cover that later.

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#ifndef HG_BDIFF_H

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#define HG_BDIFF_H

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#include "compat.h"

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struct bdiff_line {

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	int hash, n, e;

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	ssize_t len;

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	const char *l;

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};

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struct bdiff_hunk;

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struct bdiff_hunk {

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	int a1, a2, b1, b2;

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	struct bdiff_hunk *next;

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};

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int bdiff_splitlines(const char *a, ssize_t len, struct bdiff_line **lr);

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int bdiff_diff(struct bdiff_line *a, int an, struct bdiff_line *b, int bn,

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               struct bdiff_hunk *base);

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void bdiff_freehunks(struct bdiff_hunk *l);

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#endif