https://github.com/git/git
Revision 5843080c85ae9d13f77442bec7bbec8e84a18100 authored by Junio C Hamano on 02 March 2023, 16:44:16 UTC, committed by Johannes Schindelin on 22 March 2023, 16:58:29 UTC
In http.c, the run_active_slot() function allows the given "slot" to
make progress by calling step_active_slots() in a loop repeatedly,
and the loop is not left until the request held in the slot
completes.

Ages ago, we used to use the slot->in_use member to get out of the
loop, which misbehaved when the request in "slot" completes (at
which time, the result of the request is copied away from the slot,
and the in_use member is cleared, making the slot ready to be
reused), and the "slot" gets reused to service a different request
(at which time, the "slot" becomes in_use again, even though it is
for a different request).  The loop terminating condition mistakenly
thought that the original request has yet to be completed.

Today's code, after baa7b67d (HTTP slot reuse fixes, 2006-03-10)
fixed this issue, uses a separate "slot->finished" member that is
set in run_active_slot() to point to an on-stack variable, and the
code that completes the request in finish_active_slot() clears the
on-stack variable via the pointer to signal that the particular
request held by the slot has completed.  It also clears the in_use
member (as before that fix), so that the slot itself can safely be
reused for an unrelated request.

One thing that is not quite clean in this arrangement is that,
unless the slot gets reused, at which point the finished member is
reset to NULL, the member keeps the value of &finished, which
becomes a dangling pointer into the stack when run_active_slot()
returns.  Clear the finished member before the control leaves the
function, which has a side effect of unconfusing compilers like
recent GCC 12 that is over-eager to warn against such an assignment.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 321854a
Raw File
Tip revision: 5843080c85ae9d13f77442bec7bbec8e84a18100 authored by Junio C Hamano on 02 March 2023, 16:44:16 UTC
http.c: clear the 'finished' member once we are done with it
Tip revision: 5843080
convert.h
/*
 * Copyright (c) 2011, Google Inc.
 */
#ifndef CONVERT_H
#define CONVERT_H

#include "hash.h"
#include "string-list.h"

struct index_state;
struct strbuf;

#define CONV_EOL_RNDTRP_DIE   (1<<0) /* Die if CRLF to LF to CRLF is different */
#define CONV_EOL_RNDTRP_WARN  (1<<1) /* Warn if CRLF to LF to CRLF is different */
#define CONV_EOL_RENORMALIZE  (1<<2) /* Convert CRLF to LF */
#define CONV_EOL_KEEP_CRLF    (1<<3) /* Keep CRLF line endings as is */
#define CONV_WRITE_OBJECT     (1<<4) /* Content is written to the index */

extern int global_conv_flags_eol;

enum auto_crlf {
	AUTO_CRLF_FALSE = 0,
	AUTO_CRLF_TRUE = 1,
	AUTO_CRLF_INPUT = -1
};

extern enum auto_crlf auto_crlf;

enum eol {
	EOL_UNSET,
	EOL_CRLF,
	EOL_LF,
#ifdef NATIVE_CRLF
	EOL_NATIVE = EOL_CRLF
#else
	EOL_NATIVE = EOL_LF
#endif
};

enum ce_delay_state {
	CE_NO_DELAY = 0,
	CE_CAN_DELAY = 1,
	CE_RETRY = 2
};

struct delayed_checkout {
	/*
	 * State of the currently processed cache entry. If the state is
	 * CE_CAN_DELAY, then the filter can delay the current cache entry.
	 * If the state is CE_RETRY, then this signals the filter that the
	 * cache entry was requested before.
	 */
	enum ce_delay_state state;
	/* List of filter drivers that signaled delayed blobs. */
	struct string_list filters;
	/* List of delayed blobs identified by their path. */
	struct string_list paths;
};

struct checkout_metadata {
	const char *refname;
	struct object_id treeish;
	struct object_id blob;
};

extern enum eol core_eol;
extern char *check_roundtrip_encoding;
const char *get_cached_convert_stats_ascii(const struct index_state *istate,
					   const char *path);
const char *get_wt_convert_stats_ascii(const char *path);
const char *get_convert_attr_ascii(const struct index_state *istate,
				   const char *path);

/* returns 1 if *dst was used */
int convert_to_git(const struct index_state *istate,
		   const char *path, const char *src, size_t len,
		   struct strbuf *dst, int conv_flags);
int convert_to_working_tree(const struct index_state *istate,
			    const char *path, const char *src,
			    size_t len, struct strbuf *dst,
			    const struct checkout_metadata *meta);
int async_convert_to_working_tree(const struct index_state *istate,
				  const char *path, const char *src,
				  size_t len, struct strbuf *dst,
				  const struct checkout_metadata *meta,
				  void *dco);
int async_query_available_blobs(const char *cmd,
				struct string_list *available_paths);
int renormalize_buffer(const struct index_state *istate,
		       const char *path, const char *src, size_t len,
		       struct strbuf *dst);
static inline int would_convert_to_git(const struct index_state *istate,
				       const char *path)
{
	return convert_to_git(istate, path, NULL, 0, NULL, 0);
}
/* Precondition: would_convert_to_git_filter_fd(path) == true */
void convert_to_git_filter_fd(const struct index_state *istate,
			      const char *path, int fd,
			      struct strbuf *dst,
			      int conv_flags);
int would_convert_to_git_filter_fd(const struct index_state *istate,
				   const char *path);

/*
 * Initialize the checkout metadata with the given values.  Any argument may be
 * NULL if it is not applicable.  The treeish should be a commit if that is
 * available, and a tree otherwise.
 *
 * The refname is not copied and must be valid for the lifetime of the struct.
 * THe object IDs are copied.
 */
void init_checkout_metadata(struct checkout_metadata *meta, const char *refname,
			    const struct object_id *treeish,
			    const struct object_id *blob);

/* Copy the metadata from src to dst, updating the blob. */
void clone_checkout_metadata(struct checkout_metadata *dst,
			     const struct checkout_metadata *src,
			     const struct object_id *blob);

/*
 * Reset the internal list of attributes used by convert_to_git and
 * convert_to_working_tree.
 */
void reset_parsed_attributes(void);

/*****************************************************************
 *
 * Streaming conversion support
 *
 *****************************************************************/

struct stream_filter; /* opaque */

struct stream_filter *get_stream_filter(const struct index_state *istate,
					const char *path,
					const struct object_id *);
void free_stream_filter(struct stream_filter *);
int is_null_stream_filter(struct stream_filter *);

/*
 * Use as much input up to *isize_p and fill output up to *osize_p;
 * update isize_p and osize_p to indicate how much buffer space was
 * consumed and filled. Return 0 on success, non-zero on error.
 *
 * Some filters may need to buffer the input and look-ahead inside it
 * to decide what to output, and they may consume more than zero bytes
 * of input and still not produce any output. After feeding all the
 * input, pass NULL as input and keep calling this function, to let
 * such filters know there is no more input coming and it is time for
 * them to produce the remaining output based on the buffered input.
 */
int stream_filter(struct stream_filter *,
		  const char *input, size_t *isize_p,
		  char *output, size_t *osize_p);

#endif /* CONVERT_H */
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