Make tooling::applyAllReplacements return llvm::Expected<string> instead of empty string to indicate potential error.

Summary:
return llvm::Expected<> to carry error status and error information.
This is the first step towards introducing "Error" into tooling::Replacements.

Reviewers: djasper, klimek

Subscribers: ioeric, klimek, cfe-commits

Differential Revision: http://reviews.llvm.org/D21601

llvm-svn: 275062

2 files changed, 20 insertions, 14 deletions

diff --git a/clang/unittests/Tooling/RefactoringTest.cpp b/clang/unittests/Tooling/RefactoringTest.cpp
index fbf5413..df96bb1 100644
--- a/clang/unittests/Tooling/RefactoringTest.cpp
+++ b/clang/unittests/Tooling/RefactoringTest.cpp
@@ -640,27 +640,32 @@ protected:
                            StringRef Result, const Replacements &First,
                            const Replacements &Second) {
     // These are mainly to verify the test itself and make it easier to read.
-    std::string AfterFirst = applyAllReplacements(Code, First);
-    std::string InSequenceRewrite = applyAllReplacements(AfterFirst, Second);
-    EXPECT_EQ(Intermediate, AfterFirst);
-    EXPECT_EQ(Result, InSequenceRewrite);
+    auto AfterFirst = applyAllReplacements(Code, First);
+    EXPECT_TRUE(static_cast<bool>(AfterFirst));
+    auto InSequenceRewrite = applyAllReplacements(*AfterFirst, Second);
+    EXPECT_TRUE(static_cast<bool>(InSequenceRewrite));
+    EXPECT_EQ(Intermediate, *AfterFirst);
+    EXPECT_EQ(Result, *InSequenceRewrite);
 
     tooling::Replacements Merged = mergeReplacements(First, Second);
-    std::string MergedRewrite = applyAllReplacements(Code, Merged);
-    EXPECT_EQ(InSequenceRewrite, MergedRewrite);
-    if (InSequenceRewrite != MergedRewrite)
+    auto MergedRewrite = applyAllReplacements(Code, Merged);
+    EXPECT_TRUE(static_cast<bool>(MergedRewrite));
+    EXPECT_EQ(*InSequenceRewrite, *MergedRewrite);
+    if (*InSequenceRewrite != *MergedRewrite)
       for (tooling::Replacement M : Merged)
         llvm::errs() << M.getOffset() << " " << M.getLength() << " "
                      << M.getReplacementText() << "\n";
   }
   void mergeAndTestRewrite(StringRef Code, const Replacements &First,
                            const Replacements &Second) {
-    std::string InSequenceRewrite =
-        applyAllReplacements(applyAllReplacements(Code, First), Second);
+    auto AfterFirst = applyAllReplacements(Code, First);
+    EXPECT_TRUE(static_cast<bool>(AfterFirst));
+    auto InSequenceRewrite = applyAllReplacements(*AfterFirst, Second);
     tooling::Replacements Merged = mergeReplacements(First, Second);
-    std::string MergedRewrite = applyAllReplacements(Code, Merged);
-    EXPECT_EQ(InSequenceRewrite, MergedRewrite);
-    if (InSequenceRewrite != MergedRewrite)
+    auto MergedRewrite = applyAllReplacements(Code, Merged);
+    EXPECT_TRUE(static_cast<bool>(MergedRewrite));
+    EXPECT_EQ(*InSequenceRewrite, *MergedRewrite);
+    if (*InSequenceRewrite != *MergedRewrite)
       for (tooling::Replacement M : Merged)
         llvm::errs() << M.getOffset() << " " << M.getLength() << " "
                      << M.getReplacementText() << "\n";
diff --git a/clang/unittests/Tooling/RewriterTest.cpp b/clang/unittests/Tooling/RewriterTest.cpp
index 93f69eb..e8afedb 100644
--- a/clang/unittests/Tooling/RewriterTest.cpp
+++ b/clang/unittests/Tooling/RewriterTest.cpp
@@ -41,8 +41,9 @@ TEST(Rewriter, AdjacentInsertAndDelete) {
   Replacements Replaces;
   Replaces.insert(Replacement("<file>", 6, 6, ""));
   Replaces.insert(Replacement("<file>", 6, 0, "replaced\n"));
-  EXPECT_EQ("line1\nreplaced\nline3\nline4",
-            applyAllReplacements("line1\nline2\nline3\nline4", Replaces));
+  auto Rewritten = applyAllReplacements("line1\nline2\nline3\nline4", Replaces);
+  EXPECT_TRUE(static_cast<bool>(Rewritten));
+  EXPECT_EQ("line1\nreplaced\nline3\nline4", *Rewritten);
 }
 
 } // end namespace