upstream/mercurial-mirror Files · mercurial/bitmanipulation.h

merge: fix race that could cause wrong size in dirstate...

merge: fix race that could cause wrong size in dirstate The problem is that hg merge/update/etc work the following way: 1. figure out what files to update 2. apply the update to disk 3. apply the update to in-memory dirstate 4. write dirstate where step3 looks at the filesystem and assumes it sees the result of step2. If a file is changed between step2 and step3, step3 will record incorrect information in the dirstate. I avoid this by passing the size step3 needs directly from step2, for the common path (not implemented for change/delete conflicts for instance). I didn't fix the same race for the exec bit for now, because it's less likely to be problematic and I had trouble due to the fact that the dirstate stores the permissions differently from the manifest (st_mode vs '' 'l' 'x'), in combination with tests that pretend that symlinks are not supported. However, I moved the lstat from step3 to step2, which should tighten the race window markedly, both for the exec bit and for the mtime. Differential Revision: https://phab.mercurial-scm.org/D6475

Augie Fackler - - Load All Authors

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      #ifndef _HG_BITMANIPULATION_H_

      #define _HG_BITMANIPULATION_H_

      #include <string.h>

      #include "compat.h"

      static inline uint32_t getbe32(const char *c)

      {

      	const unsigned char *d = (const unsigned char *)c;

      	return ((((uint32_t)d[0]) << 24) | (((uint32_t)d[1]) << 16) |

      	        (((uint32_t)d[2]) << 8) | (d[3]));

      }

      static inline int16_t getbeint16(const char *c)

      {

      	const unsigned char *d = (const unsigned char *)c;

      	return ((d[0] << 8) | (d[1]));

      }

      static inline uint16_t getbeuint16(const char *c)

      {

      	const unsigned char *d = (const unsigned char *)c;

      	return ((d[0] << 8) | (d[1]));

      }

      static inline void putbe32(uint32_t x, char *c)

      {

      	c[0] = (x >> 24) & 0xff;

      	c[1] = (x >> 16) & 0xff;

      	c[2] = (x >> 8) & 0xff;

      	c[3] = (x)&0xff;

      }

      static inline double getbefloat64(const char *c)

      {

      	const unsigned char *d = (const unsigned char *)c;

      	double ret;

      	int i;

      	uint64_t t = 0;

      	for (i = 0; i < 8; i++) {

      		t = (t << 8) + d[i];

      	}

      	memcpy(&ret, &t, sizeof(t));

      	return ret;

      }

      #endif

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				#ifndef _HG_BITMANIPULATION_H_
				#define _HG_BITMANIPULATION_H_

				#include <string.h>

				#include "compat.h"

				static inline uint32_t getbe32(const char *c)
				{
				const unsigned char d = (const unsigned char )c;

				return ((((uint32_t)d[0]) << 24) \| (((uint32_t)d[1]) << 16) \|
				(((uint32_t)d[2]) << 8) \| (d[3]));
				}

				static inline int16_t getbeint16(const char *c)
				{
				const unsigned char d = (const unsigned char )c;

				return ((d[0] << 8) \| (d[1]));
				}

				static inline uint16_t getbeuint16(const char *c)
				{
				const unsigned char d = (const unsigned char )c;

				return ((d[0] << 8) \| (d[1]));
				}

				static inline void putbe32(uint32_t x, char *c)
				{
				c[0] = (x >> 24) & 0xff;
				c[1] = (x >> 16) & 0xff;
				c[2] = (x >> 8) & 0xff;
				c[3] = (x)&0xff;
				}

				static inline double getbefloat64(const char *c)
				{
				const unsigned char d = (const unsigned char )c;
				double ret;
				int i;
				uint64_t t = 0;
				for (i = 0; i < 8; i++) {
				t = (t << 8) + d[i];
				}
				memcpy(&ret, &t, sizeof(t));
				return ret;
				}

				#endif