lldb/source/Utility/Status.cpp

   1 //===-- Status.cpp --------------------------------------------------------===//
   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 #include "lldb/Utility/Status.h"
  10
  11 #include "lldb/Utility/VASPrintf.h"
  12 #include "lldb/lldb-defines.h"
  13 #include "lldb/lldb-enumerations.h"
  14 #include "llvm/ADT/SmallString.h"
  15 #include "llvm/ADT/StringRef.h"
  16 #include "llvm/Support/Errno.h"
  17 #include "llvm/Support/FormatProviders.h"
  18
  19 #include <cerrno>
  20 #include <cstdarg>
  21 #include <string>
  22 #include <system_error>
  23
  24 #ifdef __APPLE__
  25 #include <mach/mach.h>
  26 #endif
  27
  28 #ifdef _WIN32
  29 #include <windows.h>
  30 #endif
  31 #include <cstdint>
  32
  33 namespace llvm {
  34 class raw_ostream;
  35 }
  36
  37 using namespace lldb;
  38 using namespace lldb_private;
  39
  40 Status::Status() : m_string() {}
  41
  42 Status::Status(ValueType err, ErrorType type)
  43     : m_code(err), m_type(type), m_string() {}
  44
  45 // This logic is confusing because c++ calls the traditional (posix) errno codes
  46 // "generic errors", while we use the term "generic" to mean completely
  47 // arbitrary (text-based) errors.
  48 Status::Status(std::error_code EC)
  49     : m_code(EC.value()),
  50       m_type(EC.category() == std::generic_category() ? eErrorTypePOSIX
  51                                                       : eErrorTypeGeneric),
  52       m_string(EC.message()) {}
  53
  54 Status::Status(const char *format, ...) : m_string() {
  55   va_list args;
  56   va_start(args, format);
  57   SetErrorToGenericError();
  58   SetErrorStringWithVarArg(format, args);
  59   va_end(args);
  60 }
  61
  62 const Status &Status::operator=(llvm::Error error) {
  63   if (!error) {
  64     Clear();
  65     return *this;
  66   }
  67
  68   // if the error happens to be a errno error, preserve the error code
  69   error = llvm::handleErrors(
  70       std::move(error), [&](std::unique_ptr<llvm::ECError> e) -> llvm::Error {
  71         std::error_code ec = e->convertToErrorCode();
  72         if (ec.category() == std::generic_category()) {
  73           m_code = ec.value();
  74           m_type = ErrorType::eErrorTypePOSIX;
  75           return llvm::Error::success();
  76         }
  77         return llvm::Error(std::move(e));
  78       });
  79
  80   // Otherwise, just preserve the message
  81   if (error) {
  82     SetErrorToGenericError();
  83     SetErrorString(llvm::toString(std::move(error)));
  84   }
  85
  86   return *this;
  87 }
  88
  89 llvm::Error Status::ToError() const {
  90   if (Success())
  91     return llvm::Error::success();
  92   if (m_type == ErrorType::eErrorTypePOSIX)
  93     return llvm::errorCodeToError(
  94         std::error_code(m_code, std::generic_category()));
  95   return llvm::make_error<llvm::StringError>(AsCString(),
  96                                              llvm::inconvertibleErrorCode());
  97 }
  98
  99 Status::~Status() = default;
 100
 101 #ifdef _WIN32
 102 static std::string RetrieveWin32ErrorString(uint32_t error_code) {
 103   char *buffer = nullptr;
 104   std::string message;
 105   // Retrieve win32 system error.
 106   // First, attempt to load a en-US message
 107   if (::FormatMessageA(
 108           FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
 109               FORMAT_MESSAGE_MAX_WIDTH_MASK,
 110           NULL, error_code, MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US),
 111           (LPSTR)&buffer, 0, NULL)) {
 112     message.assign(buffer);
 113     ::LocalFree(buffer);
 114   }
 115   // If the previous didn't work, use the default OS language
 116   else if (::FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER |
 117                                 FORMAT_MESSAGE_FROM_SYSTEM |
 118                                 FORMAT_MESSAGE_MAX_WIDTH_MASK,
 119                             NULL, error_code, 0, (LPSTR)&buffer, 0, NULL)) {
 120     message.assign(buffer);
 121     ::LocalFree(buffer);
 122   }
 123   return message;
 124 }
 125 #endif
 126
 127 // Get the error value as a NULL C string. The error string will be fetched and
 128 // cached on demand. The cached error string value will remain until the error
 129 // value is changed or cleared.
 130 const char *Status::AsCString(const char *default_error_str) const {
 131   if (Success())
 132     return nullptr;
 133
 134   if (m_string.empty()) {
 135     switch (m_type) {
 136     case eErrorTypeMachKernel:
 137 #if defined(__APPLE__)
 138       if (const char *s = ::mach_error_string(m_code))
 139         m_string.assign(s);
 140 #endif
 141       break;
 142
 143     case eErrorTypePOSIX:
 144       m_string = llvm::sys::StrError(m_code);
 145       break;
 146
 147     case eErrorTypeWin32:
 148 #if defined(_WIN32)
 149       m_string = RetrieveWin32ErrorString(m_code);
 150 #endif
 151       break;
 152
 153     default:
 154       break;
 155     }
 156   }
 157   if (m_string.empty()) {
 158     if (default_error_str)
 159       m_string.assign(default_error_str);
 160     else
 161       return nullptr; // User wanted a nullptr string back...
 162   }
 163   return m_string.c_str();
 164 }
 165
 166 // Clear the error and any cached error string that it might contain.
 167 void Status::Clear() {
 168   m_code = 0;
 169   m_type = eErrorTypeInvalid;
 170   m_string.clear();
 171 }
 172
 173 // Access the error value.
 174 Status::ValueType Status::GetError() const { return m_code; }
 175
 176 // Access the error type.
 177 ErrorType Status::GetType() const { return m_type; }
 178
 179 // Returns true if this object contains a value that describes an error or
 180 // otherwise non-success result.
 181 bool Status::Fail() const { return m_code != 0; }
 182
 183 // Set accessor for the error value to "err" and the type to
 184 // "eErrorTypeMachKernel"
 185 void Status::SetMachError(uint32_t err) {
 186   m_code = err;
 187   m_type = eErrorTypeMachKernel;
 188   m_string.clear();
 189 }
 190
 191 void Status::SetExpressionError(lldb::ExpressionResults result,
 192                                 const char *mssg) {
 193   m_code = result;
 194   m_type = eErrorTypeExpression;
 195   m_string = mssg;
 196 }
 197
 198 int Status::SetExpressionErrorWithFormat(lldb::ExpressionResults result,
 199                                          const char *format, ...) {
 200   int length = 0;
 201
 202   if (format != nullptr && format[0]) {
 203     va_list args;
 204     va_start(args, format);
 205     length = SetErrorStringWithVarArg(format, args);
 206     va_end(args);
 207   } else {
 208     m_string.clear();
 209   }
 210   m_code = result;
 211   m_type = eErrorTypeExpression;
 212   return length;
 213 }
 214
 215 // Set accessor for the error value and type.
 216 void Status::SetError(ValueType err, ErrorType type) {
 217   m_code = err;
 218   m_type = type;
 219   m_string.clear();
 220 }
 221
 222 // Update the error value to be "errno" and update the type to be "POSIX".
 223 void Status::SetErrorToErrno() {
 224   m_code = errno;
 225   m_type = eErrorTypePOSIX;
 226   m_string.clear();
 227 }
 228
 229 // Update the error value to be LLDB_GENERIC_ERROR and update the type to be
 230 // "Generic".
 231 void Status::SetErrorToGenericError() {
 232   m_code = LLDB_GENERIC_ERROR;
 233   m_type = eErrorTypeGeneric;
 234   m_string.clear();
 235 }
 236
 237 // Set accessor for the error string value for a specific error. This allows
 238 // any string to be supplied as an error explanation. The error string value
 239 // will remain until the error value is cleared or a new error value/type is
 240 // assigned.
 241 void Status::SetErrorString(llvm::StringRef err_str) {
 242   if (!err_str.empty()) {
 243     // If we have an error string, we should always at least have an error set
 244     // to a generic value.
 245     if (Success())
 246       SetErrorToGenericError();
 247   }
 248   m_string = std::string(err_str);
 249 }
 250
 251 /// Set the current error string to a formatted error string.
 252 ///
 253 /// \param format
 254 ///     A printf style format string
 255 int Status::SetErrorStringWithFormat(const char *format, ...) {
 256   if (format != nullptr && format[0]) {
 257     va_list args;
 258     va_start(args, format);
 259     int length = SetErrorStringWithVarArg(format, args);
 260     va_end(args);
 261     return length;
 262   } else {
 263     m_string.clear();
 264   }
 265   return 0;
 266 }
 267
 268 int Status::SetErrorStringWithVarArg(const char *format, va_list args) {
 269   if (format != nullptr && format[0]) {
 270     // If we have an error string, we should always at least have an error set
 271     // to a generic value.
 272     if (Success())
 273       SetErrorToGenericError();
 274
 275     llvm::SmallString<1024> buf;
 276     VASprintf(buf, format, args);
 277     m_string = std::string(buf.str());
 278     return buf.size();
 279   } else {
 280     m_string.clear();
 281   }
 282   return 0;
 283 }
 284
 285 // Returns true if the error code in this object is considered a successful
 286 // return value.
 287 bool Status::Success() const { return m_code == 0; }
 288
 289 void llvm::format_provider<lldb_private::Status>::format(
 290     const lldb_private::Status &error, llvm::raw_ostream &OS,
 291     llvm::StringRef Options) {
 292   llvm::format_provider<llvm::StringRef>::format(error.AsCString(), OS,
 293                                                  Options);
 294 }