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      1 //===--- FixItRewriter.cpp - Fix-It Rewriter Diagnostic Client --*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This is a diagnostic client adaptor that performs rewrites as
     11 // suggested by code modification hints attached to diagnostics. It
     12 // then forwards any diagnostics to the adapted diagnostic client.
     13 //
     14 //===----------------------------------------------------------------------===//
     15 
     16 #include "clang/Rewrite/FixItRewriter.h"
     17 #include "clang/Basic/FileManager.h"
     18 #include "clang/Basic/SourceLocation.h"
     19 #include "clang/Basic/SourceManager.h"
     20 #include "clang/Frontend/FrontendDiagnostic.h"
     21 #include "llvm/Support/raw_ostream.h"
     22 #include "llvm/Support/Path.h"
     23 #include "llvm/ADT/OwningPtr.h"
     24 #include <cstdio>
     25 
     26 using namespace clang;
     27 
     28 FixItRewriter::FixItRewriter(Diagnostic &Diags, SourceManager &SourceMgr,
     29                              const LangOptions &LangOpts,
     30                              FixItOptions *FixItOpts)
     31   : Diags(Diags),
     32     Rewrite(SourceMgr, LangOpts),
     33     FixItOpts(FixItOpts),
     34     NumFailures(0) {
     35   Client = Diags.takeClient();
     36   Diags.setClient(this);
     37 }
     38 
     39 FixItRewriter::~FixItRewriter() {
     40   Diags.takeClient();
     41   Diags.setClient(Client);
     42 }
     43 
     44 bool FixItRewriter::WriteFixedFile(FileID ID, llvm::raw_ostream &OS) {
     45   const RewriteBuffer *RewriteBuf = Rewrite.getRewriteBufferFor(ID);
     46   if (!RewriteBuf) return true;
     47   RewriteBuf->write(OS);
     48   OS.flush();
     49   return false;
     50 }
     51 
     52 bool FixItRewriter::WriteFixedFiles() {
     53   if (NumFailures > 0 && !FixItOpts->FixWhatYouCan) {
     54     Diag(FullSourceLoc(), diag::warn_fixit_no_changes);
     55     return true;
     56   }
     57 
     58   for (iterator I = buffer_begin(), E = buffer_end(); I != E; ++I) {
     59     const FileEntry *Entry = Rewrite.getSourceMgr().getFileEntryForID(I->first);
     60     std::string Filename = FixItOpts->RewriteFilename(Entry->getName());
     61     std::string Err;
     62     llvm::raw_fd_ostream OS(Filename.c_str(), Err,
     63                             llvm::raw_fd_ostream::F_Binary);
     64     if (!Err.empty()) {
     65       Diags.Report(clang::diag::err_fe_unable_to_open_output)
     66           << Filename << Err;
     67       continue;
     68     }
     69     RewriteBuffer &RewriteBuf = I->second;
     70     RewriteBuf.write(OS);
     71     OS.flush();
     72   }
     73 
     74   return false;
     75 }
     76 
     77 bool FixItRewriter::IncludeInDiagnosticCounts() const {
     78   return Client ? Client->IncludeInDiagnosticCounts() : true;
     79 }
     80 
     81 void FixItRewriter::HandleDiagnostic(Diagnostic::Level DiagLevel,
     82                                      const DiagnosticInfo &Info) {
     83   // Default implementation (Warnings/errors count).
     84   DiagnosticClient::HandleDiagnostic(DiagLevel, Info);
     85 
     86   Client->HandleDiagnostic(DiagLevel, Info);
     87 
     88   // Skip over any diagnostics that are ignored or notes.
     89   if (DiagLevel <= Diagnostic::Note)
     90     return;
     91 
     92   // Make sure that we can perform all of the modifications we
     93   // in this diagnostic.
     94   bool CanRewrite = Info.getNumFixItHints() > 0;
     95   for (unsigned Idx = 0, Last = Info.getNumFixItHints();
     96        Idx < Last; ++Idx) {
     97     const FixItHint &Hint = Info.getFixItHint(Idx);
     98     if (Hint.RemoveRange.isValid() &&
     99         Rewrite.getRangeSize(Hint.RemoveRange) == -1) {
    100       CanRewrite = false;
    101       break;
    102     }
    103   }
    104 
    105   if (!CanRewrite) {
    106     if (Info.getNumFixItHints() > 0)
    107       Diag(Info.getLocation(), diag::note_fixit_in_macro);
    108 
    109     // If this was an error, refuse to perform any rewriting.
    110     if (DiagLevel == Diagnostic::Error || DiagLevel == Diagnostic::Fatal) {
    111       if (++NumFailures == 1)
    112         Diag(Info.getLocation(), diag::note_fixit_unfixed_error);
    113     }
    114     return;
    115   }
    116 
    117   bool Failed = false;
    118   for (unsigned Idx = 0, Last = Info.getNumFixItHints();
    119        Idx < Last; ++Idx) {
    120     const FixItHint &Hint = Info.getFixItHint(Idx);
    121 
    122     if (Hint.CodeToInsert.empty()) {
    123       // We're removing code.
    124       if (Rewrite.RemoveText(Hint.RemoveRange))
    125         Failed = true;
    126       continue;
    127     }
    128 
    129     // We're replacing code.
    130     if (Rewrite.ReplaceText(Hint.RemoveRange.getBegin(),
    131                             Rewrite.getRangeSize(Hint.RemoveRange),
    132                             Hint.CodeToInsert))
    133       Failed = true;
    134   }
    135 
    136   if (Failed) {
    137     ++NumFailures;
    138     Diag(Info.getLocation(), diag::note_fixit_failed);
    139     return;
    140   }
    141 
    142   Diag(Info.getLocation(), diag::note_fixit_applied);
    143 }
    144 
    145 /// \brief Emit a diagnostic via the adapted diagnostic client.
    146 void FixItRewriter::Diag(SourceLocation Loc, unsigned DiagID) {
    147   // When producing this diagnostic, we temporarily bypass ourselves,
    148   // clear out any current diagnostic, and let the downstream client
    149   // format the diagnostic.
    150   Diags.takeClient();
    151   Diags.setClient(Client);
    152   Diags.Clear();
    153   Diags.Report(Loc, DiagID);
    154   Diags.takeClient();
    155   Diags.setClient(this);
    156 }
    157 
    158 FixItOptions::~FixItOptions() {}
    159