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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/Frontend/FixItRewriter.h"
     17 #include "clang/Basic/FileManager.h"
     18 #include "clang/Basic/SourceLocation.h"
     19 #include "clang/Basic/SourceManager.h"
     20 #include "clang/Edit/Commit.h"
     21 #include "clang/Edit/EditsReceiver.h"
     22 #include "clang/Frontend/FrontendDiagnostic.h"
     23 #include "llvm/Support/Path.h"
     24 #include "llvm/Support/raw_ostream.h"
     25 #include <cstdio>
     26 #include <memory>
     27 
     28 using namespace clang;
     29 
     30 FixItRewriter::FixItRewriter(DiagnosticsEngine &Diags, SourceManager &SourceMgr,
     31                              const LangOptions &LangOpts,
     32                              FixItOptions *FixItOpts)
     33   : Diags(Diags),
     34     Editor(SourceMgr, LangOpts),
     35     Rewrite(SourceMgr, LangOpts),
     36     FixItOpts(FixItOpts),
     37     NumFailures(0),
     38     PrevDiagSilenced(false) {
     39   OwnsClient = Diags.ownsClient();
     40   Client = Diags.takeClient();
     41   Diags.setClient(this);
     42 }
     43 
     44 FixItRewriter::~FixItRewriter() {
     45   Diags.takeClient();
     46   Diags.setClient(Client, OwnsClient);
     47 }
     48 
     49 bool FixItRewriter::WriteFixedFile(FileID ID, raw_ostream &OS) {
     50   const RewriteBuffer *RewriteBuf = Rewrite.getRewriteBufferFor(ID);
     51   if (!RewriteBuf) return true;
     52   RewriteBuf->write(OS);
     53   OS.flush();
     54   return false;
     55 }
     56 
     57 namespace {
     58 
     59 class RewritesReceiver : public edit::EditsReceiver {
     60   Rewriter &Rewrite;
     61 
     62 public:
     63   RewritesReceiver(Rewriter &Rewrite) : Rewrite(Rewrite) { }
     64 
     65   void insert(SourceLocation loc, StringRef text) override {
     66     Rewrite.InsertText(loc, text);
     67   }
     68   void replace(CharSourceRange range, StringRef text) override {
     69     Rewrite.ReplaceText(range.getBegin(), Rewrite.getRangeSize(range), text);
     70   }
     71 };
     72 
     73 }
     74 
     75 bool FixItRewriter::WriteFixedFiles(
     76             std::vector<std::pair<std::string, std::string> > *RewrittenFiles) {
     77   if (NumFailures > 0 && !FixItOpts->FixWhatYouCan) {
     78     Diag(FullSourceLoc(), diag::warn_fixit_no_changes);
     79     return true;
     80   }
     81 
     82   RewritesReceiver Rec(Rewrite);
     83   Editor.applyRewrites(Rec);
     84 
     85   for (iterator I = buffer_begin(), E = buffer_end(); I != E; ++I) {
     86     const FileEntry *Entry = Rewrite.getSourceMgr().getFileEntryForID(I->first);
     87     int fd;
     88     std::string Filename = FixItOpts->RewriteFilename(Entry->getName(), fd);
     89     std::string Err;
     90     std::unique_ptr<llvm::raw_fd_ostream> OS;
     91     if (fd != -1) {
     92       OS.reset(new llvm::raw_fd_ostream(fd, /*shouldClose=*/true));
     93     } else {
     94       OS.reset(new llvm::raw_fd_ostream(Filename.c_str(), Err,
     95                                         llvm::sys::fs::F_None));
     96     }
     97     if (!Err.empty()) {
     98       Diags.Report(clang::diag::err_fe_unable_to_open_output)
     99           << Filename << Err;
    100       continue;
    101     }
    102     RewriteBuffer &RewriteBuf = I->second;
    103     RewriteBuf.write(*OS);
    104     OS->flush();
    105 
    106     if (RewrittenFiles)
    107       RewrittenFiles->push_back(std::make_pair(Entry->getName(), Filename));
    108   }
    109 
    110   return false;
    111 }
    112 
    113 bool FixItRewriter::IncludeInDiagnosticCounts() const {
    114   return Client ? Client->IncludeInDiagnosticCounts() : true;
    115 }
    116 
    117 void FixItRewriter::HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
    118                                      const Diagnostic &Info) {
    119   // Default implementation (Warnings/errors count).
    120   DiagnosticConsumer::HandleDiagnostic(DiagLevel, Info);
    121 
    122   if (!FixItOpts->Silent ||
    123       DiagLevel >= DiagnosticsEngine::Error ||
    124       (DiagLevel == DiagnosticsEngine::Note && !PrevDiagSilenced) ||
    125       (DiagLevel > DiagnosticsEngine::Note && Info.getNumFixItHints())) {
    126     Client->HandleDiagnostic(DiagLevel, Info);
    127     PrevDiagSilenced = false;
    128   } else {
    129     PrevDiagSilenced = true;
    130   }
    131 
    132   // Skip over any diagnostics that are ignored or notes.
    133   if (DiagLevel <= DiagnosticsEngine::Note)
    134     return;
    135   // Skip over errors if we are only fixing warnings.
    136   if (DiagLevel >= DiagnosticsEngine::Error && FixItOpts->FixOnlyWarnings) {
    137     ++NumFailures;
    138     return;
    139   }
    140 
    141   // Make sure that we can perform all of the modifications we
    142   // in this diagnostic.
    143   edit::Commit commit(Editor);
    144   for (unsigned Idx = 0, Last = Info.getNumFixItHints();
    145        Idx < Last; ++Idx) {
    146     const FixItHint &Hint = Info.getFixItHint(Idx);
    147 
    148     if (Hint.CodeToInsert.empty()) {
    149       if (Hint.InsertFromRange.isValid())
    150         commit.insertFromRange(Hint.RemoveRange.getBegin(),
    151                            Hint.InsertFromRange, /*afterToken=*/false,
    152                            Hint.BeforePreviousInsertions);
    153       else
    154         commit.remove(Hint.RemoveRange);
    155     } else {
    156       if (Hint.RemoveRange.isTokenRange() ||
    157           Hint.RemoveRange.getBegin() != Hint.RemoveRange.getEnd())
    158         commit.replace(Hint.RemoveRange, Hint.CodeToInsert);
    159       else
    160         commit.insert(Hint.RemoveRange.getBegin(), Hint.CodeToInsert,
    161                     /*afterToken=*/false, Hint.BeforePreviousInsertions);
    162     }
    163   }
    164   bool CanRewrite = Info.getNumFixItHints() > 0 && commit.isCommitable();
    165 
    166   if (!CanRewrite) {
    167     if (Info.getNumFixItHints() > 0)
    168       Diag(Info.getLocation(), diag::note_fixit_in_macro);
    169 
    170     // If this was an error, refuse to perform any rewriting.
    171     if (DiagLevel >= DiagnosticsEngine::Error) {
    172       if (++NumFailures == 1)
    173         Diag(Info.getLocation(), diag::note_fixit_unfixed_error);
    174     }
    175     return;
    176   }
    177 
    178   if (!Editor.commit(commit)) {
    179     ++NumFailures;
    180     Diag(Info.getLocation(), diag::note_fixit_failed);
    181     return;
    182   }
    183 
    184   Diag(Info.getLocation(), diag::note_fixit_applied);
    185 }
    186 
    187 /// \brief Emit a diagnostic via the adapted diagnostic client.
    188 void FixItRewriter::Diag(SourceLocation Loc, unsigned DiagID) {
    189   // When producing this diagnostic, we temporarily bypass ourselves,
    190   // clear out any current diagnostic, and let the downstream client
    191   // format the diagnostic.
    192   Diags.takeClient();
    193   Diags.setClient(Client);
    194   Diags.Clear();
    195   Diags.Report(Loc, DiagID);
    196   Diags.takeClient();
    197   Diags.setClient(this);
    198 }
    199 
    200 FixItOptions::~FixItOptions() {}
    201