clang/tools/libclang/CLog.h

   1 //===- CLog.h - Logging Interface -------------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_CLANG_TOOLS_LIBCLANG_CLOG_H
  10 #define LLVM_CLANG_TOOLS_LIBCLANG_CLOG_H
  11
  12 #include "clang-c/Index.h"
  13 #include "clang/Basic/FileEntry.h"
  14 #include "clang/Basic/LLVM.h"
  15 #include "llvm/ADT/IntrusiveRefCntPtr.h"
  16 #include "llvm/ADT/SmallString.h"
  17 #include "llvm/ADT/StringRef.h"
  18 #include "llvm/Support/Compiler.h"
  19 #include "llvm/Support/raw_ostream.h"
  20 #include <string>
  21
  22 namespace llvm {
  23 class format_object_base;
  24 }
  25
  26 namespace clang {
  27 namespace cxindex {
  28
  29 class Logger;
  30 typedef IntrusiveRefCntPtr<Logger> LogRef;
  31
  32 /// Collects logging output and writes it to stderr when it's destructed.
  33 /// Common use case:
  34 /// \code
  35 ///   if (LogRef Log = Logger::make(__func__)) {
  36 ///     *Log << "stuff";
  37 ///   }
  38 /// \endcode
  39 class Logger : public RefCountedBase<Logger> {
  40   std::string Name;
  41   bool Trace;
  42   SmallString<64> Msg;
  43   llvm::raw_svector_ostream LogOS;
  44 public:
  45   static const char *getEnvVar() {
  46     static const char *sCachedVar = ::getenv("LIBCLANG_LOGGING");
  47     return sCachedVar;
  48   }
  49   static bool isLoggingEnabled() { return getEnvVar() != nullptr; }
  50   static bool isStackTracingEnabled() {
  51     if (const char *EnvOpt = Logger::getEnvVar())
  52       return llvm::StringRef(EnvOpt) == "2";
  53     return false;
  54   }
  55   static LogRef make(llvm::StringRef name,
  56                      bool trace = isStackTracingEnabled()) {
  57     if (isLoggingEnabled())
  58       return new Logger(name, trace);
  59     return nullptr;
  60   }
  61
  62   explicit Logger(llvm::StringRef name, bool trace)
  63       : Name(std::string(name)), Trace(trace), LogOS(Msg) {}
  64   ~Logger();
  65
  66   Logger &operator<<(CXTranslationUnit);
  67   Logger &operator<<(FileEntryRef FE);
  68   Logger &operator<<(CXCursor cursor);
  69   Logger &operator<<(CXSourceLocation);
  70   Logger &operator<<(CXSourceRange);
  71   Logger &operator<<(CXString);
  72   Logger &operator<<(llvm::StringRef Str) { LogOS << Str; return *this; }
  73   Logger &operator<<(const char *Str) {
  74     if (Str)
  75       LogOS << Str;
  76     return *this;
  77   }
  78   Logger &operator<<(unsigned long N) { LogOS << N; return *this; }
  79   Logger &operator<<(long N) { LogOS << N ; return *this; }
  80   Logger &operator<<(unsigned int N) { LogOS << N; return *this; }
  81   Logger &operator<<(int N) { LogOS << N; return *this; }
  82   Logger &operator<<(char C) { LogOS << C; return *this; }
  83   Logger &operator<<(unsigned char C) { LogOS << C; return *this; }
  84   Logger &operator<<(signed char C) { LogOS << C; return *this; }
  85   Logger &operator<<(const llvm::format_object_base &Fmt);
  86 };
  87
  88 }
  89 }
  90
  91 /// Macros to automate common uses of Logger. Like this:
  92 /// \code
  93 ///   LOG_FUNC_SECTION {
  94 ///     *Log << "blah";
  95 ///   }
  96 /// \endcode
  97 #define LOG_SECTION(NAME) \
  98     if (clang::cxindex::LogRef Log = clang::cxindex::Logger::make(NAME))
  99 #define LOG_FUNC_SECTION LOG_SECTION(__func__)
 100
 101 #endif