Add base::ExecutableExistsInPath

base/files/file_util_posix.cc

Index: base/files/file_util_posix.cc
diff --git a/base/files/file_util_posix.cc b/base/files/file_util_posix.cc
index ca1c5250b920d310e0be12acb2a73a5cede3bddc..42de9316f1c9b02aa803feb8113c6a03d958e5c7 100644
--- a/base/files/file_util_posix.cc
+++ b/base/files/file_util_posix.cc
@@ -22,6 +22,7 @@
 #include <time.h>
 #include <unistd.h>
 
+#include "base/environment.h"
 #include "base/files/file_enumerator.h"
 #include "base/files/file_path.h"
 #include "base/files/scoped_file.h"
@@ -31,6 +32,7 @@
 #include "base/path_service.h"
 #include "base/posix/eintr_wrapper.h"
 #include "base/stl_util.h"
+#include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/sys_string_conversions.h"
@@ -455,6 +457,25 @@ bool SetPosixFilePermissions(const FilePath& path,
   return true;
 }
 
+bool ExecutableExistsInPath(Environment* env,
+                            const FilePath::StringType& executable) {
+  std::string path;
+  if (!env->GetVar("PATH", &path)) {
+    LOG(ERROR) << "No $PATH variable. Assuming no " << executable << ".";
+    return false;
+  }
+
+  for (const StringPiece& cur_path :
+       SplitStringPiece(path, ":", KEEP_WHITESPACE, SPLIT_WANT_NONEMPTY)) {
+    FilePath file(cur_path);
+    int permissions;
+    if (GetPosixFilePermissions(file.Append(executable), &permissions) &&
+        (permissions & FILE_PERMISSION_EXECUTE_BY_USER))
+      return true;
+  }
+  return false;
+}
+
 #if !defined(OS_MACOSX)
 // This is implemented in file_util_mac.mm for Mac.
 bool GetTempDir(FilePath* path) {