From 52ed867801b3ddb5569b7f823e63555e9c322c99 Mon Sep 17 00:00:00 2001
From: "Michael J. Spencer" <bigcheesegs@gmail.com>
Date: Wed, 1 Dec 2010 00:52:55 +0000
Subject: [PATCH] Support/PathV2: Add replace_extension implementation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120514 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Support/PathV2.cpp     | 20 ++++++++++++++++++++
 unittests/Support/Path.cpp |  4 ++++
 2 files changed, 24 insertions(+)

diff --git a/lib/Support/PathV2.cpp b/lib/Support/PathV2.cpp
index df401bd46ba..7e49d8d446a 100644
--- a/lib/Support/PathV2.cpp
+++ b/lib/Support/PathV2.cpp
@@ -511,6 +511,26 @@ error_code remove_filename(SmallVectorImpl<char> &path) {
   return make_error_code(errc::success);
 }
 
+error_code replace_extension(SmallVectorImpl<char> &path,
+                             const Twine &extension) {
+  StringRef p(path.begin(), path.size());
+  SmallString<32> ext_storage;
+  StringRef ext = extension.toStringRef(ext_storage);
+
+  // Erase existing extension.
+  size_t pos = p.find_last_of('.');
+  if (pos != StringRef::npos && pos >= filename_pos(p))
+    path.set_size(pos);
+
+  // Append '.' if needed.
+  if (ext.size() > 0 && ext[0] != '.')
+    path.push_back('.');
+
+  // Append extension.
+  path.append(ext.begin(), ext.end());
+  return make_error_code(errc::success);
+}
+
 }
 }
 }
diff --git a/unittests/Support/Path.cpp b/unittests/Support/Path.cpp
index 5ab74e14f70..823b0780300 100644
--- a/unittests/Support/Path.cpp
+++ b/unittests/Support/Path.cpp
@@ -103,6 +103,10 @@ TEST(Support, Path) {
     if (error_code ec = sys::path::remove_filename(temp_store))
       ASSERT_FALSE(ec.message().c_str());
     outs() << "    remove_filename: " << temp_store << '\n';
+    temp_store = *i;
+    if (error_code ec = sys::path::replace_extension(temp_store, "ext"))
+      ASSERT_FALSE(ec.message().c_str());
+    outs() << "    replace_extension: " << temp_store << '\n';
 
     outs().flush();
   }