1 files changed, 194 insertions, 0 deletions
diff --git a/Source/cmTimestamp.cxx b/Source/cmTimestamp.cxx
new file mode 100644
index 0000000..13f73dc
--- /dev/null
+++ b/Source/cmTimestamp.cxx
@@ -0,0 +1,194 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+
+#if !defined(_WIN32) && !defined(__sun)
+// POSIX APIs are needed
+#  define _POSIX_C_SOURCE 200809L
+#endif
+#if defined(__OpenBSD__) || defined(__FreeBSD__) || defined(__NetBSD__)
+// For isascii
+#  define _XOPEN_SOURCE 700
+#endif
+
+#include "cmTimestamp.h"
+
+#include <cstdlib>
+#include <cstring>
+#include <sstream>
+
+#include "cmStringAlgorithms.h"
+#include "cmSystemTools.h"
+
+std::string cmTimestamp::CurrentTime(const std::string& formatString,
+                                     bool utcFlag)
+{
+  time_t currentTimeT = time(nullptr);
+  std::string source_date_epoch;
+  cmSystemTools::GetEnv("SOURCE_DATE_EPOCH", source_date_epoch);
+  if (!source_date_epoch.empty()) {
+    std::istringstream iss(source_date_epoch);
+    iss >> currentTimeT;
+    if (iss.fail() || !iss.eof()) {
+      cmSystemTools::Error("Cannot parse SOURCE_DATE_EPOCH as integer");
+      exit(27);
+    }
+  }
+  if (currentTimeT == time_t(-1)) {
+    return std::string();
+  }
+
+  return CreateTimestampFromTimeT(currentTimeT, formatString, utcFlag);
+}
+
+std::string cmTimestamp::FileModificationTime(const char* path,
+                                              const std::string& formatString,
+                                              bool utcFlag)
+{
+  std::string real_path =
+    cmSystemTools::GetRealPathResolvingWindowsSubst(path);
+
+  if (!cmsys::SystemTools::FileExists(real_path)) {
+    return std::string();
+  }
+
+  time_t mtime = cmsys::SystemTools::ModifiedTime(real_path);
+  return CreateTimestampFromTimeT(mtime, formatString, utcFlag);
+}
+
+std::string cmTimestamp::CreateTimestampFromTimeT(time_t timeT,
+                                                  std::string formatString,
+                                                  bool utcFlag) const
+{
+  if (formatString.empty()) {
+    formatString = "%Y-%m-%dT%H:%M:%S";
+    if (utcFlag) {
+      formatString += "Z";
+    }
+  }
+
+  struct tm timeStruct;
+  memset(&timeStruct, 0, sizeof(timeStruct));
+
+  struct tm* ptr = nullptr;
+  if (utcFlag) {
+    ptr = gmtime(&timeT);
+  } else {
+    ptr = localtime(&timeT);
+  }
+
+  if (ptr == nullptr) {
+    return std::string();
+  }
+
+  timeStruct = *ptr;
+
+  std::string result;
+  for (std::string::size_type i = 0; i < formatString.size(); ++i) {
+    char c1 = formatString[i];
+    char c2 = (i + 1 < formatString.size()) ? formatString[i + 1]
+                                            : static_cast<char>(0);
+
+    if (c1 == '%' && c2 != 0) {
+      result += AddTimestampComponent(c2, timeStruct, timeT);
+      ++i;
+    } else {
+      result += c1;
+    }
+  }
+
+  return result;
+}
+
+time_t cmTimestamp::CreateUtcTimeTFromTm(struct tm& tm) const
+{
+#if defined(_MSC_VER) && _MSC_VER >= 1400
+  return _mkgmtime(&tm);
+#else
+  // From Linux timegm() manpage.
+
+  std::string tz_old;
+  bool const tz_was_set = cmSystemTools::GetEnv("TZ", tz_old);
+  tz_old = "TZ=" + tz_old;
+
+  // The standard says that "TZ=" or "TZ=[UNRECOGNIZED_TZ]" means UTC.
+  // It seems that "TZ=" does NOT work, at least under Windows
+  // with neither MSVC nor MinGW, so let's use explicit "TZ=UTC"
+
+  cmSystemTools::PutEnv("TZ=UTC");
+
+  tzset();
+
+  time_t result = mktime(&tm);
+
+#  ifndef CMAKE_BOOTSTRAP
+  if (tz_was_set) {
+    cmSystemTools::PutEnv(tz_old);
+  } else {
+    cmSystemTools::UnsetEnv("TZ");
+  }
+#  else
+  // No UnsetEnv during bootstrap.  This is good enough for CMake itself.
+  cmSystemTools::PutEnv(tz_old);
+  static_cast<void>(tz_was_set);
+#  endif
+
+  tzset();
+
+  return result;
+#endif
+}
+
+std::string cmTimestamp::AddTimestampComponent(char flag,
+                                               struct tm& timeStruct,
+                                               const time_t timeT) const
+{
+  std::string formatString = cmStrCat('%', flag);
+
+  switch (flag) {
+    case 'a':
+    case 'A':
+    case 'b':
+    case 'B':
+    case 'd':
+    case 'H':
+    case 'I':
+    case 'j':
+    case 'm':
+    case 'M':
+    case 'S':
+    case 'U':
+    case 'w':
+    case 'y':
+    case 'Y':
+    case '%':
+      break;
+    case 's': // Seconds since UNIX epoch (midnight 1-jan-1970)
+    {
+      // Build a time_t for UNIX epoch and substract from the input "timeT":
+      struct tm tmUnixEpoch;
+      memset(&tmUnixEpoch, 0, sizeof(tmUnixEpoch));
+      tmUnixEpoch.tm_mday = 1;
+      tmUnixEpoch.tm_year = 1970 - 1900;
+
+      const time_t unixEpoch = this->CreateUtcTimeTFromTm(tmUnixEpoch);
+      if (unixEpoch == -1) {
+        cmSystemTools::Error(
+          "Error generating UNIX epoch in "
+          "STRING(TIMESTAMP ...). Please, file a bug report against CMake");
+        return std::string();
+      }
+
+      return std::to_string(static_cast<long int>(difftime(timeT, unixEpoch)));
+    }
+    default: {
+      return formatString;
+    }
+  }
+
+  char buffer[16];
+
+  size_t size =
+    strftime(buffer, sizeof(buffer), formatString.c_str(), &timeStruct);
+
+  return std::string(buffer, size);
+}