echo/CMake
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

cmFileTime: Fix overflow on time computation

Browse Source 
On Windows, time starting point is Januray, 1st of 1601.
So computing number of nanoseconds from this date exceeds 64bit
capabilities.
This commit is contained in:
Marc Chevrier 2020-11-23 15:03:25 +01:00
parent 4549027a09
commit b4c994f69c
2 changed files with 40 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
Source/cmFileTime.cxx
View File

@ -24,13 +24,13 @@ bool cmFileTime::Load(std::string const& fileName)
}
# if CMake_STAT_HAS_ST_MTIM
// Nanosecond resolution
this->NS = fst.st_mtim.tv_sec * NsPerS + fst.st_mtim.tv_nsec;
this->Time = fst.st_mtim.tv_sec * UtPerS + fst.st_mtim.tv_nsec;
# elif CMake_STAT_HAS_ST_MTIMESPEC
// Nanosecond resolution
this->NS = fst.st_mtimespec.tv_sec * NsPerS + fst.st_mtimespec.tv_nsec;
this->Time = fst.st_mtimespec.tv_sec * UtPerS + fst.st_mtimespec.tv_nsec;
# else
// Second resolution
this->NS = fst.st_mtime * NsPerS;
this->Time = fst.st_mtime * UtPerS;
# endif
#else
// Windows version. Get the modification time from extended file attributes.
@ -41,10 +41,11 @@ bool cmFileTime::Load(std::string const& fileName)
}
// Copy the file time to the output location.
this->NS = (static_cast<NSC>(fdata.ftLastWriteTime.dwHighDateTime) << 32) |
static_cast<NSC>(fdata.ftLastWriteTime.dwLowDateTime);
// The file time resolution is 100 ns.
this->NS *= 100;
using uint64 = unsigned long long;
this->Time = static_cast<TimeType>(
(uint64(fdata.ftLastWriteTime.dwHighDateTime) << 32) +
fdata.ftLastWriteTime.dwLowDateTime);
#endif
return true;
}

52
Source/cmFileTime.h
View File

@ -13,9 +13,15 @@
class cmFileTime
{
public:
using NSC = long long;
static constexpr NSC NsPerS = 1000000000;
using TimeType = long long;
// unit time per second
#if !defined(_WIN32) || defined(__CYGWIN__)
// unit time is one nanosecond
static constexpr TimeType UtPerS = 1000000000;
#else
// unit time is 100 nanosecond
static constexpr TimeType UtPerS = 10000000;
#endif
cmFileTime() = default;
~cmFileTime() = default;
@ -28,22 +34,28 @@ public:
/**
* @brief Return true if this is older than ftm
*/
bool Older(cmFileTime const& ftm) const { return (this->NS - ftm.NS) < 0; }
bool Older(cmFileTime const& ftm) const
{
return (this->Time - ftm.Time) < 0;
}
/**
* @brief Return true if this is newer than ftm
*/
bool Newer(cmFileTime const& ftm) const { return (ftm.NS - this->NS) < 0; }
bool Newer(cmFileTime const& ftm) const
{
return (ftm.Time - this->Time) < 0;
}
/**
* @brief Return true if this is the same as ftm
*/
bool Equal(cmFileTime const& ftm) const { return this->NS == ftm.NS; }
bool Equal(cmFileTime const& ftm) const { return this->Time == ftm.Time; }
/**
* @brief Return true if this is not the same as ftm
*/
bool Differ(cmFileTime const& ftm) const { return this->NS != ftm.NS; }
bool Differ(cmFileTime const& ftm) const { return this->Time != ftm.Time; }
/**
* @brief Compare file modification times.
@ -51,7 +63,7 @@ public:
*/
int Compare(cmFileTime const& ftm) const
{
NSC const diff = this->NS - ftm.NS;
TimeType const diff = this->Time - ftm.Time;
if (diff == 0) {
return 0;
}
@ -65,7 +77,7 @@ public:
*/
bool OlderS(cmFileTime const& ftm) const
{
return (ftm.NS - this->NS) >= cmFileTime::NsPerS;
return (ftm.Time - this->Time) >= cmFileTime::UtPerS;
}
/**
@ -73,7 +85,7 @@ public:
*/
bool NewerS(cmFileTime const& ftm) const
{
return (this->NS - ftm.NS) >= cmFileTime::NsPerS;
return (this->Time - ftm.Time) >= cmFileTime::UtPerS;
}
/**
@ -81,11 +93,11 @@ public:
*/
bool EqualS(cmFileTime const& ftm) const
{
NSC diff = this->NS - ftm.NS;
TimeType diff = this->Time - ftm.Time;
if (diff < 0) {
diff = -diff;
}
return (diff < cmFileTime::NsPerS);
return (diff < cmFileTime::UtPerS);
}
/**
@ -93,11 +105,11 @@ public:
*/
bool DifferS(cmFileTime const& ftm) const
{
NSC diff = this->NS - ftm.NS;
TimeType diff = this->Time - ftm.Time;
if (diff < 0) {
diff = -diff;
}
return (diff >= cmFileTime::NsPerS);
return (diff >= cmFileTime::UtPerS);
}
/**
@ -107,21 +119,21 @@ public:
*/
int CompareS(cmFileTime const& ftm) const
{
NSC const diff = this->NS - ftm.NS;
if (diff <= -cmFileTime::NsPerS) {
TimeType const diff = this->Time - ftm.Time;
if (diff <= -cmFileTime::UtPerS) {
return -1;
}
if (diff >= cmFileTime::NsPerS) {
if (diff >= cmFileTime::UtPerS) {
return 1;
}
return 0;
}
/**
* @brief The file modification time in nanoseconds
* @brief The file modification time in unit time per second
*/
NSC GetNS() const { return this->NS; }
TimeType GetTime() const { return this->Time; }
private:
NSC NS = 0;
TimeType Time = 0;
};