add support for utils::guesspath() on macos

src/utils.cpp

@@ -32,6 +32,11 @@
 #include <unistd.h>    // for readlink
 #endif
 
+#if defined(__APPLE__)
+#include <sys/syslimits.h>
+#include <fcntl.h>     // for fcntl
+#endif
+
 /*! \file utils.cpp */
 
 /*
@@ -162,6 +167,13 @@ const char *utils::guesspath(char *buf, int len, FILE *fp)
   // get pathname from /proc or copy (unknown)
   if (readlink(fmt::format("/proc/self/fd/{}", fd).c_str(), buf, len - 1) <= 0)
     strncpy(buf, "(unknown)", len - 1);
+#elif defined(__APPLE__)
+  int fd = fileno(fp);
+  char filepath[PATH_MAX];
+  if (fcntl(fd,F_GETPATH,filepath) != -1)
+    strncpy(buf, filepath, len - 1);
+  else
+    strncpy(buf, "(unknown)", len - 1);
 #else
   strncpy(buf, "(unknown)", len - 1);
 #endif

src/utils.h

@@ -408,7 +408,7 @@ namespace utils {
 
   /*! Try to detect pathname from FILE pointer.
    *
-   * Currently only supported on Linux, otherwise will report "(unknown)".
+   * Currently only supported on Linux and macOS, otherwise will report "(unknown)".
    *
    *  \param buf  storage buffer for pathname. output will be truncated if not large enough
    *  \param len  size of storage buffer. output will be truncated to this length - 1

unittest/utils/test_utils.cpp

@@ -722,7 +722,7 @@ TEST(Utils, guesspath)
 {
     char buf[256];
     FILE *fp = fopen("test_guesspath.txt", "w");
-#if defined(__linux__)
+#if defined(__linux__) || (__APPLE__)
     const char *path = utils::guesspath(buf, sizeof(buf), fp);
     ASSERT_THAT(path, EndsWith("test_guesspath.txt"));
 #else