libdeno: add file utilities Dirname() and ExePath()

1 files changed, 59 insertions, 0 deletions

diff --git a/libdeno/file_util.cc b/libdeno/file_util.cc
index a0cae5f58..8df0dafea 100644
--- a/libdeno/file_util.cc
+++ b/libdeno/file_util.cc
@@ -1,10 +1,21 @@
 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 #include <inttypes.h>
+#include <limits.h>
+#include <stdint.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <fstream>
 #include <iterator>
 #include <string>
 
+#ifdef __APPLE__
+#include <mach-o/dyld.h>
+#endif
+
+#ifdef _WIN32
+#include <windows.h>
+#endif
+
 #include "file_util.h"
 
 namespace deno {
@@ -28,4 +39,52 @@ std::string Basename(std::string const& filename) {
   return filename;
 }
 
+// Returns the directory component from a filename. The returned path always
+// ends with a slash. This function does not understand Windows drive letters.
+std::string Dirname(std::string const& filename) {
+  for (auto it = filename.rbegin(); it != filename.rend(); ++it) {
+    char ch = *it;
+    if (ch == '\\' || ch == '/') {
+      return std::string(filename.begin(), it.base());
+    }
+  }
+  return std::string("./");
+}
+
+// Returns the full path the currently running executable.
+// This implementation is very basic. Caveats:
+//   * OS X: fails if buffer is too small, does not retry with a bigger buffer.
+//   * Windows: ANSI only, no unicode. Fails if path is longer than 260 chars.
+bool ExePath(std::string* path) {
+#ifdef _WIN32
+  // Windows only.
+  char exe_buf[MAX_PATH];
+  DWORD len = GetModuleFileNameA(NULL, exe_buf, sizeof exe_buf);
+  if (len == 0 || len == sizeof exe_buf) {
+    return false;
+  }
+#else
+#ifdef __APPLE__
+  // OS X only.
+  char link_buf[PATH_MAX * 2];  // Exe may be longer than MAX_PATH, says Apple.
+  uint32_t len = sizeof link_buf;
+  if (_NSGetExecutablePath(link_buf, &len) < 0) {
+    return false;
+  }
+#else
+  // Linux only.
+  static const char* link_buf = "/proc/self/exe";
+#endif
+  // Linux and OS X.
+  char exe_buf[PATH_MAX];
+  char* r = realpath(link_buf, exe_buf);
+  if (r == NULL) {
+    return false;
+  }
+#endif
+  // All platforms.
+  path->assign(exe_buf);
+  return true;
+}
+
 }  // namespace deno