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Revision 663b2b1b90bf76275044824ddeca96aaec240f09 authored by Derrick Stolee on 17 September 2020, 18:11:46 UTC, committed by Junio C Hamano on 17 September 2020, 18:30:05 UTC 
maintenance: add commit-graph task
 
The first new task in the 'git maintenance' builtin is the
'commit-graph' task. This updates the commit-graph file
incrementally with the command

	git commit-graph write --reachable --split

By writing an incremental commit-graph file using the "--split"
option we minimize the disruption from this operation. The default
behavior is to merge layers until the new "top" layer is less than
half the size of the layer below. This provides quick writes most
of the time, with the longer writes following a power law
distribution.

Most importantly, concurrent Git processes only look at the
commit-graph-chain file for a very short amount of time, so they
will verly likely not be holding a handle to the file when we try
to replace it. (This only matters on Windows.)

If a concurrent process reads the old commit-graph-chain file, but
our job expires some of the .graph files before they can be read,
then those processes will see a warning message (but not fail).
This could be avoided by a future update to use the --expire-time
argument when writing the commit-graph.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 3103e98
Raw File
remote-fd.c 
#include "builtin.h"
#include "transport.h"

static const char usage_msg[] =
	"git remote-fd <remote> <url>";

/*
 * URL syntax:
 *	'fd::<inoutfd>[/<anything>]'		Read/write socket pair
 *						<inoutfd>.
 *	'fd::<infd>,<outfd>[/<anything>]'	Read pipe <infd> and write
 *						pipe <outfd>.
 *	[foo] indicates 'foo' is optional. <anything> is any string.
 *
 * The data output to <outfd>/<inoutfd> should be passed unmolested to
 * git-receive-pack/git-upload-pack/git-upload-archive and output of
 * git-receive-pack/git-upload-pack/git-upload-archive should be passed
 * unmolested to <infd>/<inoutfd>.
 *
 */

#define MAXCOMMAND 4096

static void command_loop(int input_fd, int output_fd)
{
	char buffer[MAXCOMMAND];

	while (1) {
		size_t i;
		if (!fgets(buffer, MAXCOMMAND - 1, stdin)) {
			if (ferror(stdin))
				die("Input error");
			return;
		}
		/* Strip end of line characters. */
		i = strlen(buffer);
		while (i > 0 && isspace(buffer[i - 1]))
			buffer[--i] = 0;

		if (!strcmp(buffer, "capabilities")) {
			printf("*connect\n\n");
			fflush(stdout);
		} else if (!strncmp(buffer, "connect ", 8)) {
			printf("\n");
			fflush(stdout);
			if (bidirectional_transfer_loop(input_fd,
				output_fd))
				die("Copying data between file descriptors failed");
			return;
		} else {
			die("Bad command: %s", buffer);
		}
	}
}

int cmd_remote_fd(int argc, const char **argv, const char *prefix)
{
	int input_fd = -1;
	int output_fd = -1;
	char *end;

	if (argc != 3)
		usage(usage_msg);

	input_fd = (int)strtoul(argv[2], &end, 10);

	if ((end == argv[2]) || (*end != ',' && *end != '/' && *end))
		die("Bad URL syntax");

	if (*end == '/' || !*end) {
		output_fd = input_fd;
	} else {
		char *end2;
		output_fd = (int)strtoul(end + 1, &end2, 10);

		if ((end2 == end + 1) || (*end2 != '/' && *end2))
			die("Bad URL syntax");
	}

	command_loop(input_fd, output_fd);
	return 0;
}
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