diff options
Diffstat (limited to 'zen/file_io.cpp')
| -rw-r--r-- | zen/file_io.cpp | 93 |
1 files changed, 43 insertions, 50 deletions
diff --git a/zen/file_io.cpp b/zen/file_io.cpp index b385ce33..b4351ee8 100644 --- a/zen/file_io.cpp +++ b/zen/file_io.cpp @@ -152,6 +152,7 @@ FileInput::FileInput(const Zstring& filepath) : //throw FileError, ErrorFileLock #ifdef ZEN_WIN //destructor call would lead to member double clean-up!!! ZEN_ON_SCOPE_FAIL(::CloseHandle(fileHandle)); + #elif defined ZEN_LINUX || defined ZEN_MAC ZEN_ON_SCOPE_FAIL(::close(fileHandle)); #endif @@ -178,45 +179,38 @@ FileInput::~FileInput() } -size_t FileInput::read(void* buffer, size_t bytesToRead) //throw FileError; returns actual number of bytes read +size_t FileInput::tryRead(void* buffer, size_t bytesToRead) //throw FileError; may return short, only 0 means EOF! { - size_t bytesReadTotal = 0; + if (bytesToRead == 0) //"read() with a count of 0 returns zero" => indistinguishable from end of file! => check! + throw std::logic_error("Contract violation! " + std::string(__FILE__) + ":" + numberTo<std::string>(__LINE__)); - while (bytesToRead > 0) //"read() with a count of 0 returns zero" => indistinguishable from end of file! => check! - { #ifdef ZEN_WIN - //test for end of file: https://msdn.microsoft.com/en-us/library/windows/desktop/aa365690%28v=vs.85%29.aspx - DWORD bytesRead = 0; - if (!::ReadFile(fileHandle, //__in HANDLE hFile, - buffer, //__out LPVOID lpBuffer, - static_cast<DWORD>(bytesToRead), //__in DWORD nNumberOfBytesToRead, - &bytesRead, //__out_opt LPDWORD lpNumberOfBytesRead, - nullptr)) //__inout_opt LPOVERLAPPED lpOverlapped - THROW_LAST_FILE_ERROR(replaceCpy(_("Cannot read file %x."), L"%x", fmtPath(getFilePath())), L"ReadFile"); + //posix ::read() semantics: test for end of file: https://msdn.microsoft.com/en-us/library/windows/desktop/aa365690%28v=vs.85%29.aspx + DWORD bytesRead = 0; + if (!::ReadFile(fileHandle, //__in HANDLE hFile, + buffer, //__out LPVOID lpBuffer, + static_cast<DWORD>(bytesToRead), //__in DWORD nNumberOfBytesToRead, + &bytesRead, //__out_opt LPDWORD lpNumberOfBytesRead, + nullptr)) //__inout_opt LPOVERLAPPED lpOverlapped + THROW_LAST_FILE_ERROR(replaceCpy(_("Cannot read file %x."), L"%x", fmtPath(getFilePath())), L"ReadFile"); #elif defined ZEN_LINUX || defined ZEN_MAC - ssize_t bytesRead = 0; - do - { - bytesRead = ::read(fileHandle, buffer, bytesToRead); - } - while (bytesRead < 0 && errno == EINTR); //Compare copy_reg() in copy.c: ftp://ftp.gnu.org/gnu/coreutils/coreutils-8.23.tar.xz + ssize_t bytesRead = 0; + do + { + bytesRead = ::read(fileHandle, buffer, bytesToRead); + } + while (bytesRead < 0 && errno == EINTR); //Compare copy_reg() in copy.c: ftp://ftp.gnu.org/gnu/coreutils/coreutils-8.23.tar.xz - if (bytesRead < 0) - THROW_LAST_FILE_ERROR(replaceCpy(_("Cannot read file %x."), L"%x", fmtPath(getFilePath())), L"read"); + if (bytesRead < 0) + THROW_LAST_FILE_ERROR(replaceCpy(_("Cannot read file %x."), L"%x", fmtPath(getFilePath())), L"read"); #endif - if (bytesRead == 0) //"zero indicates end of file" - return bytesReadTotal; + if (static_cast<size_t>(bytesRead) > bytesToRead) //better safe than sorry + throw FileError(replaceCpy(_("Cannot read file %x."), L"%x", fmtPath(getFilePath())), L"ReadFile: buffer overflow."); //user should never see this - if (static_cast<size_t>(bytesRead) > bytesToRead) //better safe than sorry - throw FileError(replaceCpy(_("Cannot read file %x."), L"%x", fmtPath(getFilePath())), L"ReadFile: buffer overflow."); //user should never see this + //if ::read is interrupted (EINTR) right in the middle, it will return successfully with "bytesRead < bytesToRead" => loop! - //if ::read is interrupted (EINTR) right in the middle, it will return successfully with "bytesRead < bytesToRead" => loop! - buffer = static_cast<char*>(buffer) + bytesRead; //suppress warning about pointer arithmetics on void* - bytesToRead -= bytesRead; - bytesReadTotal += bytesRead; - } - return bytesReadTotal; + return bytesRead; //"zero indicates end of file" } //---------------------------------------------------------------------------------------------------- @@ -355,8 +349,11 @@ void FileOutput::close() //throw FileError } -void FileOutput::write(const void* buffer, size_t bytesToWrite) //throw FileError +size_t FileOutput::tryWrite(const void* buffer, size_t bytesToWrite) //throw FileError; may return short! CONTRACT: bytesToWrite > 0 { + if (bytesToWrite == 0) + throw std::logic_error("Contract violation! " + std::string(__FILE__) + ":" + numberTo<std::string>(__LINE__)); + #ifdef ZEN_WIN DWORD bytesWritten = 0; //this parameter is NOT optional: http://blogs.msdn.com/b/oldnewthing/archive/2013/04/04/10407417.aspx if (!::WriteFile(fileHandle, //__in HANDLE hFile, @@ -370,28 +367,24 @@ void FileOutput::write(const void* buffer, size_t bytesToWrite) //throw FileErro throw FileError(replaceCpy(_("Cannot write file %x."), L"%x", fmtPath(getFilePath())), L"WriteFile: incomplete write."); //user should never see this #elif defined ZEN_LINUX || defined ZEN_MAC - while (bytesToWrite > 0) + ssize_t bytesWritten = 0; + do { - ssize_t bytesWritten = 0; - do - { - bytesWritten = ::write(fileHandle, buffer, bytesToWrite); - } - while (bytesWritten < 0 && errno == EINTR); - - if (bytesWritten <= 0) - { - if (bytesWritten == 0) //comment in safe-read.c suggests to treat this as an error due to buggy drivers - errno = ENOSPC; + bytesWritten = ::write(fileHandle, buffer, bytesToWrite); + } + while (bytesWritten < 0 && errno == EINTR); - THROW_LAST_FILE_ERROR(replaceCpy(_("Cannot write file %x."), L"%x", fmtPath(getFilePath())), L"write"); - } - if (bytesWritten > static_cast<ssize_t>(bytesToWrite)) //better safe than sorry - throw FileError(replaceCpy(_("Cannot write file %x."), L"%x", fmtPath(getFilePath())), L"write: buffer overflow."); //user should never see this + if (bytesWritten <= 0) + { + if (bytesWritten == 0) //comment in safe-read.c suggests to treat this as an error due to buggy drivers + errno = ENOSPC; - //if ::write() is interrupted (EINTR) right in the middle, it will return successfully with "bytesWritten < bytesToWrite"! - buffer = static_cast<const char*>(buffer) + bytesWritten; //suppress warning about pointer arithmetics on void* - bytesToWrite -= bytesWritten; + THROW_LAST_FILE_ERROR(replaceCpy(_("Cannot write file %x."), L"%x", fmtPath(getFilePath())), L"write"); } + if (bytesWritten > static_cast<ssize_t>(bytesToWrite)) //better safe than sorry + throw FileError(replaceCpy(_("Cannot write file %x."), L"%x", fmtPath(getFilePath())), L"write: buffer overflow."); //user should never see this + + //if ::write() is interrupted (EINTR) right in the middle, it will return successfully with "bytesWritten < bytesToWrite"! #endif + return bytesWritten; } |