[PATCH] Introduce llvm::sys::path::home_directory.

[Aaron Ballman]

On Sun, Nov 17, 2013 at 5:55 AM, Peter Collingbourne <peter at pcc.me.uk> wrote:
> This will be used by the line editor library to derive a default path to
> the history file.
>
> I've verified that the Windows bits build (with a mingw64 cross compiler)
> but I haven't actually tested them.
>
> http://llvm-reviews.chandlerc.com/D2199
>
> Files:
>   include/llvm/Support/Path.h
>   lib/Support/Unix/Path.inc
>   lib/Support/Windows/Path.inc
>   unittests/Support/Path.cpp
>
> Index: include/llvm/Support/Path.h
> ===================================================================
> --- include/llvm/Support/Path.h
> +++ include/llvm/Support/Path.h
> @@ -306,6 +306,12 @@
>  /// @param result Holds the resulting path name.
>  void system_temp_directory(bool erasedOnReboot, SmallVectorImpl<char> &result);
>
> +/// @brief Get the user's home directory.
> +///
> +/// @param result Holds the resulting path name.
> +/// @result True if a home directory is set, false otherwise.
> +bool home_directory(SmallVectorImpl<char> &result);
> +
>  /// @brief Has root name?
>  ///
>  /// root_name != ""
> Index: lib/Support/Unix/Path.inc
> ===================================================================
> --- lib/Support/Unix/Path.inc
> +++ lib/Support/Unix/Path.inc
> @@ -793,5 +793,19 @@
>  }
>
>  } // end namespace fs
> +
> +namespace path {
> +
> +bool home_directory(SmallVectorImpl<char> &result) {
> +  if (char *RequestedDir = getenv("HOME")) {
> +    result.append(RequestedDir, RequestedDir + strlen(RequestedDir));

This behavior differs from the Windows implementation in that it's
appending to the results instead of replacing them.

> +    return true;
> +  }
> +
> +  return false;
> +}
> +
> +} // end namespace path
> +
>  } // end namespace sys
>  } // end namespace llvm
> Index: lib/Support/Windows/Path.inc
> ===================================================================
> --- lib/Support/Windows/Path.inc
> +++ lib/Support/Windows/Path.inc
> @@ -20,6 +20,7 @@
>  #include "Windows.h"
>  #include <fcntl.h>
>  #include <io.h>
> +#include <shlobj.h>
>  #include <sys/stat.h>
>  #include <sys/types.h>
>
> @@ -1061,6 +1062,22 @@
>  }
>  } // end namespace fs
>
> +namespace path {
> +
> +bool home_directory(SmallVectorImpl<char> &result) {
> +  wchar_t Path[MAX_PATH];

The documentation is a bit cagey on this -- it says "a null terminated
string of length MAX_PATH", which I take to mean you need to allocate
MAX_PATH + 1 characters for the edge case where you're returned a
string of length MAX_PATH.

> +  if (::SHGetFolderPathW(0, CSIDL_APPDATA | CSIDL_FLAG_CREATE, 0,
> +                         SHGFP_TYPE_CURRENT, Path) != S_OK)

You shouldn't be passing CSIDL_FLAG_CREATE here; if the user has no
home directory, it should fail as in the unix case.  Also, as a total
nitpick, I'd prefer to see use of the FAILED macro instead of checking
the result directly.  Eg)

if (FAILED(::SHGetFolderPath(...))

> +    return false;
> +
> +  if (UTF16ToUTF8(Path, ::wcslen(Path), result))
> +    return false;
> +
> +  return true;
> +}
> +
> +} // end namespace path
> +
>  namespace windows {
>  llvm::error_code UTF8ToUTF16(llvm::StringRef utf8,
>                               llvm::SmallVectorImpl<wchar_t> &utf16) {
> Index: unittests/Support/Path.cpp
> ===================================================================
> --- unittests/Support/Path.cpp
> +++ unittests/Support/Path.cpp
> @@ -210,6 +210,19 @@
>  }
>  #endif // LLVM_ON_WIN32
>
> +TEST(Support, HomeDirectory) {
> +#ifdef LLVM_ON_UNIX
> +  // This test only makes sense on Unix if $HOME is set.
> +  if (::getenv("HOME")) {
> +#endif
> +    SmallString<128> HomeDir;
> +    EXPECT_TRUE(path::home_directory(HomeDir));
> +    EXPECT_FALSE(HomeDir.empty());
> +#ifdef LLVM_ON_UNIX
> +  }
> +#endif
> +}
> +
>  class FileSystemTest : public testing::Test {
>  protected:
>    /// Unique temporary directory in which all created filesystem entities must
>
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~Aaron