diff options
| -rw-r--r-- | apt-pkg/contrib/fileutl.cc | 133 |
1 files changed, 57 insertions, 76 deletions
diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc index 162ad7e8d..c4ff36a13 100644 --- a/apt-pkg/contrib/fileutl.cc +++ b/apt-pkg/contrib/fileutl.cc @@ -922,9 +922,27 @@ bool ChangeOwnerAndPermissionOfFile(char const * const requester, char const * c class APT_HIDDEN FileFdPrivate { /*{{{*/ protected: FileFd * const filefd; - const size_t buffersize_max = 4096; - std::unique_ptr<char[]> buffer; - unsigned long long buffersize = 0; + struct simple_buffer { + static constexpr size_t buffersize_max = 4096; + unsigned long long bufferstart = 0; + unsigned long long bufferend = 0; + char buffer[buffersize_max]; + + char *get() { return buffer + bufferstart; } + bool empty() { return bufferend <= bufferstart; } + unsigned long long size() { return bufferend-bufferstart; } + void reset() { bufferend = bufferstart = 0; } + ssize_t read(void *to, unsigned long long requested_size) + { + if (size() < requested_size) + requested_size = size(); + memcpy(to, buffer + bufferstart, requested_size); + bufferstart += requested_size; + if (bufferstart == bufferend) + bufferstart = bufferend = 0; + return requested_size; + } + } buffer; public: int compressed_fd; pid_t compressor_pid; @@ -932,40 +950,19 @@ public: APT::Configuration::Compressor compressor; unsigned int openmode; unsigned long long seekpos; - explicit FileFdPrivate(FileFd * const pfilefd) : filefd(pfilefd), buffer(nullptr), + explicit FileFdPrivate(FileFd * const pfilefd) : filefd(pfilefd), compressed_fd(-1), compressor_pid(-1), is_pipe(false), openmode(0), seekpos(0) {}; virtual bool InternalOpen(int const iFd, unsigned int const Mode) = 0; ssize_t InternalRead(void * To, unsigned long long Size) { - unsigned long long tmp = 0; - if (buffersize != 0) + // Drain the buffer if needed. + if (buffer.empty() == false) { - if (buffersize >= Size) - { - memcpy(To, buffer.get(), Size); - if (buffersize == Size) - { - buffersize = 0; - } - else - { - buffersize -= Size; - memmove(buffer.get(), buffer.get() + Size, buffersize); - } - return Size; - } - else - { - memcpy(To, buffer.get(), buffersize); - Size -= buffersize; - To = static_cast<char *>(To) + buffersize; - tmp = buffersize; - buffersize = 0; - } + return buffer.read(To, Size); } - return InternalUnbufferedRead(To, Size) + tmp; + return InternalUnbufferedRead(To, Size); } virtual ssize_t InternalUnbufferedRead(void * const To, unsigned long long const Size) = 0; virtual bool InternalReadError() { return filefd->FileFdErrno("read",_("Read error")); } @@ -980,19 +977,15 @@ public: char * const InitialTo = To; do { - if (buffersize == 0) + if (buffer.empty() == true) { - if (buffer.get() == nullptr) - { - buffer.reset(new char[buffersize_max]); - } + buffer.reset(); unsigned long long actualread = 0; - if (filefd->Read(buffer.get(), buffersize_max, &actualread) == false) + if (filefd->Read(buffer.get(), buffer.buffersize_max, &actualread) == false) return nullptr; - buffersize = actualread; - if (buffersize == 0) + buffer.bufferend = actualread; + if (buffer.size() == 0) { - buffer.reset(nullptr); if (To == InitialTo) return nullptr; break; @@ -1000,30 +993,20 @@ public: filefd->Flags &= ~FileFd::HitEof; } - unsigned long long const OutputSize = std::min(Size, buffersize); + unsigned long long const OutputSize = std::min(Size, buffer.size()); char const * const newline = static_cast<char const * const>(memchr(buffer.get(), '\n', OutputSize)); if (newline != nullptr) { - size_t length = (newline - buffer.get()); - ++length; - memcpy(To, buffer.get(), length); + size_t length = (newline - buffer.get()) + 1; + buffer.read(To, length); To += length; - if (length < buffersize) - { - buffersize -= length; - memmove(buffer.get(), buffer.get() + length, buffersize); - } - else - buffersize = 0; break; } else { - memcpy(To, buffer.get(), OutputSize); + buffer.read(To, OutputSize); To += OutputSize; Size -= OutputSize; - buffersize -= OutputSize; - memmove(buffer.get(), buffer.get() + OutputSize, buffersize); } } while (Size > 0); *To = '\0'; @@ -1062,7 +1045,7 @@ public: if (filefd->OpenInternDescriptor(openmode, compressor) == false) return filefd->FileFdError("Seek on file %s because it couldn't be reopened", filefd->FileName.c_str()); - buffersize = 0; + buffer.reset(); if (To != 0) return filefd->Skip(To); @@ -1092,7 +1075,7 @@ public: // seeking around, but not all users of FileFd use always Seek() and co // so d->seekpos isn't always true and we can just use it as a hint if // we have nothing else, but not always as an authority… - return seekpos - buffersize; + return seekpos - buffer.size(); } virtual unsigned long long InternalSize() { @@ -1168,20 +1151,19 @@ public: if (res != (off_t)To) return filefd->FileFdError("Unable to seek to %llu", To); seekpos = To; - buffersize = 0; + buffer.reset(); return true; } virtual bool InternalSkip(unsigned long long Over) override { - if (Over >= buffersize) + if (Over >= buffer.size()) { - Over -= buffersize; - buffersize = 0; + Over -= buffer.size(); + buffer.reset(); } else { - buffersize -= Over; - memmove(buffer.get(), buffer.get() + Over, buffersize); + buffer.bufferstart += Over; return true; } if (Over == 0) @@ -1194,7 +1176,7 @@ public: } virtual unsigned long long InternalTell() override { - return gztell(gz) - buffersize; + return gztell(gz) - buffer.size(); } virtual unsigned long long InternalSize() override { @@ -1628,10 +1610,10 @@ public: virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) override { // files opened read+write are strange and only really "supported" for direct files - if (buffersize != 0) + if (buffer.size() != 0) { - lseek(filefd->iFd, -buffersize, SEEK_CUR); - buffersize = 0; + lseek(filefd->iFd, -buffer.size(), SEEK_CUR); + buffer.reset(); } return write(filefd->iFd, From, Size); } @@ -1641,20 +1623,19 @@ public: if (res != (off_t)To) return filefd->FileFdError("Unable to seek to %llu", To); seekpos = To; - buffersize = 0; + buffer.reset(); return true; } virtual bool InternalSkip(unsigned long long Over) override { - if (Over >= buffersize) + if (Over >= buffer.size()) { - Over -= buffersize; - buffersize = 0; + Over -= buffer.size(); + buffer.reset(); } else { - buffersize -= Over; - memmove(buffer.get(), buffer.get() + Over, buffersize); + buffer.bufferstart += Over; return true; } if (Over == 0) @@ -1667,15 +1648,15 @@ public: } virtual bool InternalTruncate(unsigned long long const To) override { - if (buffersize != 0) + if (buffer.size() != 0) { unsigned long long const seekpos = lseek(filefd->iFd, 0, SEEK_CUR); - if ((seekpos - buffersize) >= To) - buffersize = 0; + if ((seekpos - buffer.size()) >= To) + buffer.reset(); else if (seekpos >= To) - buffersize = (To - seekpos); + buffer.bufferend = (To - seekpos) + buffer.bufferstart; else - buffersize = 0; + buffer.reset(); } if (ftruncate(filefd->iFd, To) != 0) return filefd->FileFdError("Unable to truncate to %llu",To); @@ -1683,7 +1664,7 @@ public: } virtual unsigned long long InternalTell() override { - return lseek(filefd->iFd,0,SEEK_CUR) - buffersize; + return lseek(filefd->iFd,0,SEEK_CUR) - buffer.size(); } virtual unsigned long long InternalSize() override { |