Push the rewriting APIs along. Build a trivial client that replaces tabs

with x's for now.  The APIs are all unimplemented, so it doesn't do 
anything yet! :)


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@42868 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 58 insertions, 8 deletions

diff --git a/Driver/RewriteTest.cpp b/Driver/RewriteTest.cpp
index ef1a9b0822..9e32c8c211 100644
--- a/Driver/RewriteTest.cpp
+++ b/Driver/RewriteTest.cpp
@@ -12,32 +12,82 @@
 //===----------------------------------------------------------------------===//
 
 #include "ASTConsumers.h"
+#include "clang/Rewrite/Rewriter.h"
 #include "clang/AST/AST.h"
 #include "clang/AST/ASTConsumer.h"
-
+#include "clang/Basic/SourceManager.h"
 using namespace clang;
 
 
 namespace {
-  class ASTViewer : public ASTConsumer {
+  class RewriteTest : public ASTConsumer {
     SourceManager *SM;
+    unsigned MainFileID;
   public:
-    void Initialize(ASTContext &Context, unsigned MainFileID) {
+    void Initialize(ASTContext &Context, unsigned mainFileID) {
       SM = &Context.SourceMgr;
+      MainFileID = mainFileID;
     }
     
     virtual void HandleTopLevelDecl(Decl *D);
+
+    
+    ~RewriteTest();
   };
 }
 
-ASTConsumer *clang::CreateCodeRewriterTest() { return new ASTViewer(); }
-
+ASTConsumer *clang::CreateCodeRewriterTest() { return new RewriteTest(); }
 
-
-
-void ASTViewer::HandleTopLevelDecl(Decl *D) {
+void RewriteTest::HandleTopLevelDecl(Decl *D) {
+  // Nothing to do here yet.
+#if 0
   if (NamedDecl *ND = dyn_cast<NamedDecl>(D))
     if (ND->getName())
       printf("%s\n", ND->getName());
+#endif
+}
+
+
+
+RewriteTest::~RewriteTest() {
+  Rewriter Rewrite(*SM);
+  
+  // Get the top-level buffer that this corresponds to.
+  std::pair<const char*, const char*> MainBuf = SM->getBufferData(MainFileID);
+  const char *MainBufStart = MainBuf.first;
+  const char *MainBufEnd = MainBuf.second;
+  
+  // Loop over the whole file, looking for tabs.
+  for (const char *BufPtr = MainBufStart; BufPtr != MainBufEnd; ++BufPtr) {
+    if (*BufPtr != '\t')
+      continue;
+    
+    // Okay, we found a tab.  This tab will turn into at least one character,
+    // but it depends on which 'virtual column' it is in.  Compute that now.
+    unsigned VCol = 0;
+    while (BufPtr-VCol != MainBufStart && BufPtr[-VCol-1] != '\t' &&
+           BufPtr[-VCol-1] != '\n' && BufPtr[-VCol-1] != '\r')
+      ++VCol;
+    
+    // Okay, now that we know the virtual column, we know how many spaces to
+    // insert.  We assume 8-character tab-stops.
+    unsigned Spaces = 8-(VCol & 7);
+    
+    // Get the location of the tab.
+    SourceLocation TabLoc =
+      SourceLocation::getFileLoc(MainFileID, BufPtr-MainBufStart);
+    
+    // Rewrite the single tab character into a sequence of spaces.
+    Rewrite.ReplaceText(TabLoc, 1, "xxxxxxxxxxx", Spaces);
+  }
   
+  // Get the buffer corresponding to MainFileID.  If we haven't changed it, then
+  // we are done.
+  if (const RewriteBuffer *RewriteBuf = 
+          Rewrite.getRewriteBufferFor(MainFileID)) {
+    RewriteBuf = 0;
+    printf("Changed\n");
+  } else {
+    printf("No changes\n");
+  }
 }