Reapply "[llvm-cov] Add an -output-dir option for the show sub-command""

Passing -output-dir path/to/dir to llvm-cov show creates path/to/dir if
it doesn't already exist, and prints reports into that directory.

In function view mode, all views are written into
path/to/dir/functions.$EXTENSION. In file view mode, all views are
written into path/to/dir/coverage/$PATH.$EXTENSION.

Changes since the initial commit:

- Avoid accidentally closing stdout twice.

llvm-svn: 273985

1 files changed, 26 insertions, 1 deletions

diff --git a/llvm/tools/llvm-cov/SourceCoverageView.h b/llvm/tools/llvm-cov/SourceCoverageView.h
index 03c0742..def5c6a 100644
--- a/llvm/tools/llvm-cov/SourceCoverageView.h
+++ b/llvm/tools/llvm-cov/SourceCoverageView.h
@@ -101,7 +101,7 @@ struct LineCoverageStats {
 ///
 /// A source coverage view and its nested sub-views form a file-oriented
 /// representation of code coverage data. This view can be printed out by a
-/// renderer which implements the Rendering Interface.
+/// renderer which implements both the File Creation and Rendering interfaces.
 class SourceCoverageView {
   /// A function or file name.
   StringRef SourceName;
@@ -122,6 +122,25 @@ class SourceCoverageView {
   /// on display.
   std::vector<InstantiationView> InstantiationSubViews;
 
+public:
+  struct StreamDestructor {
+    void operator()(raw_ostream *OS) const;
+  };
+
+  using OwnedStream = std::unique_ptr<raw_ostream, StreamDestructor>;
+
+  /// @name File Creation Interface
+  /// @{
+
+  /// \brief Create a file to print a coverage view into.
+  virtual Expected<OwnedStream> createOutputFile(StringRef Path,
+                                                 bool InToplevel) = 0;
+
+  /// \brief Close a file which has been used to print a coverage view.
+  virtual void closeOutputFile(OwnedStream OS) = 0;
+
+  /// @}
+
 protected:
   struct LineRef {
     StringRef Line;
@@ -183,6 +202,12 @@ protected:
   /// digits.
   static std::string formatCount(uint64_t N);
 
+  /// \brief If directory output is enabled, create a file with \p Path as the
+  /// suffix. Otherwise, return stdout.
+  static Expected<OwnedStream>
+  createOutputStream(const CoverageViewOptions &Opts, StringRef Path,
+                     StringRef Extension, bool InToplevel);
+
   SourceCoverageView(StringRef SourceName, const MemoryBuffer &File,
                      const CoverageViewOptions &Options,
                      coverage::CoverageData &&CoverageInfo)