support for removing a statement as a whole

Change-Id: Icb7b017a0c76a6169f0f629bb40bf97449c75837

2 files changed, 57 insertions, 10 deletions

diff --git a/compilerplugins/clang/plugin.cxx b/compilerplugins/clang/plugin.cxx
index 6535e1a96471..22bac0cdfe8c 100644
--- a/compilerplugins/clang/plugin.cxx
+++ b/compilerplugins/clang/plugin.cxx
@@ -105,22 +105,47 @@ bool RewritePlugin::insertTextBefore( SourceLocation Loc, StringRef Str )
 
 bool RewritePlugin::removeText( SourceLocation Start, unsigned Length, RewriteOptions opts )
     {
-    if( rewriter.RemoveText( Start, Length, opts ))
-        return reportEditFailure( Start );
-    return true;
+    return removeText( SourceRange( Start, Start.getLocWithOffset( Length )), opts );
     }
 
-bool RewritePlugin::removeText( CharSourceRange range, RewriteOptions opts )
+bool RewritePlugin::removeText( SourceRange range, RewriteOptions opts )
     {
+    if( opts.RemoveWholeStatement )
+        {
+        if( !adjustForWholeStatement( &range ))
+            return reportEditFailure( range.getBegin());
+        }
     if( rewriter.RemoveText( range, opts ))
         return reportEditFailure( range.getBegin());
     return true;
     }
 
-bool RewritePlugin::removeText( SourceRange range, RewriteOptions opts )
+bool RewritePlugin::adjustForWholeStatement( SourceRange* range )
     {
-    if( rewriter.RemoveText( range, opts ))
-        return reportEditFailure( range.getBegin());
+    SourceManager& SM = rewriter.getSourceMgr();
+    SourceLocation fileStartLoc = SM.getLocForStartOfFile( SM.getFileID( range->getBegin()));
+    if( fileStartLoc.isInvalid())
+        return false;
+    bool invalid = false;
+    const char* fileBuf = SM.getCharacterData( fileStartLoc, &invalid );
+    if( invalid )
+        return false;
+    const char* startBuf = SM.getCharacterData( range->getBegin(), &invalid );
+    if( invalid )
+        return false;
+    const char* endBuf = SM.getCharacterData( range->getEnd(), &invalid );
+    if( invalid )
+        return false;
+    const char* startSpacePos = startBuf;
+    // do not skip \n here, RemoveLineIfEmpty can take care of that
+    --startSpacePos;
+    while( startSpacePos >= fileBuf && ( *startSpacePos == ' ' || *startSpacePos == '\t' ))
+        --startSpacePos;
+    const char* semiPos = strchr( endBuf, ';' );
+    if( semiPos == NULL )
+        return false;
+    *range = SourceRange( range->getBegin().getLocWithOffset( startSpacePos - startBuf + 1 ),
+        range->getEnd().getLocWithOffset( semiPos - endBuf + 1 ));
     return true;
     }
 
diff --git a/compilerplugins/clang/plugin.hxx b/compilerplugins/clang/plugin.hxx
index 2a587addcb54..b9409b2cfc1c 100644
--- a/compilerplugins/clang/plugin.hxx
+++ b/compilerplugins/clang/plugin.hxx
@@ -44,18 +44,39 @@ class RewritePlugin
     public:
         explicit RewritePlugin( ASTContext& context, Rewriter& rewriter );
     protected:
-        typedef Rewriter::RewriteOptions RewriteOptions;
+        // This enum allows passing just 'RemoveLineIfEmpty' to functions below.
+        enum RemoveLineIfEmpty_t { RemoveLineIfEmpty };
+        // Use this to remove the declaration/statement as a whole, i.e. all whitespace before the statement
+        // and the trailing semicolor (is not part of the AST element range itself).
+        // The trailing semicolon must be present.
+        enum RemoveWholeStatement_t { RemoveWholeStatement };
+        enum RemoveLineIfEmptyAndWholeStatement_t { RemoveLineIfEmptyAndWholeStatement };
+        // syntactic sugar to be able to write 'RemoveLineIfEmpty | RemoveWholeStatement'
+        friend RemoveLineIfEmptyAndWholeStatement_t operator|( RemoveLineIfEmpty_t, RemoveWholeStatement_t )
+            { return RemoveLineIfEmptyAndWholeStatement; }
+        struct RewriteOptions
+            : public Rewriter::RewriteOptions
+            {
+            RewriteOptions() : RemoveWholeStatement( false ) {} // default
+            RewriteOptions( RemoveLineIfEmpty_t ) : RemoveWholeStatement( false ) { RemoveLineIfEmpty = true; }
+            RewriteOptions( RemoveWholeStatement_t ) : RemoveWholeStatement( true ) {}
+            RewriteOptions( RemoveLineIfEmptyAndWholeStatement_t ) : RemoveWholeStatement( true ) { RemoveLineIfEmpty = true; }
+            bool RemoveWholeStatement;
+            };
         // These following insert/remove/replaceText functions map to functions
-        // in clang::Rewriter, with two differences:
+        // in clang::Rewriter, with these differences:
         // - they (more intuitively) return false on failure rather than true
         // - they report a warning when the change cannot be done
+        // - There is RemoveWholeStatement to also remove the trailing semicolon when removing (must be there)
+        //   and al preceding whitespace.
         bool insertText( SourceLocation Loc, StringRef Str,
             bool InsertAfter = true, bool indentNewLines = false );
         bool insertTextAfter( SourceLocation Loc, StringRef Str );
         bool insertTextAfterToken( SourceLocation Loc, StringRef Str );
         bool insertTextBefore( SourceLocation Loc, StringRef Str );
         bool removeText( SourceLocation Start, unsigned Length, RewriteOptions opts = RewriteOptions());
-        bool removeText( CharSourceRange range, RewriteOptions opts = RewriteOptions());
+        // CharSourceRange not supported, unless really needed, as it makes RemoveSemicolon more complicated
+        //bool removeText( CharSourceRange range, RewriteOptions opts = RewriteOptions());
         bool removeText( SourceRange range, RewriteOptions opts = RewriteOptions());
         bool replaceText( SourceLocation Start, unsigned OrigLength, StringRef NewStr );
         bool replaceText( SourceRange range, StringRef NewStr );
@@ -63,6 +84,7 @@ class RewritePlugin
         Rewriter& rewriter;
     private:
         bool reportEditFailure( SourceLocation loc );
+        bool adjustForWholeStatement( SourceRange* range );
     };
 
 inline