| //===--- llvm/Support/DataStream.cpp - Lazy streamed Data ---===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements DataStreamer, which fetches bytes of Data from |
| // a stream source. It provides support for streaming (lazy reading) of |
| // bitcode. An example implementation of streaming from a file or stdin |
| // is included. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #define DEBUG_TYPE "Data-stream" |
| #include "llvm/ADT/Statistic.h" |
| #include "llvm/Support/DataStream.h" |
| #include "llvm/Support/system_error.h" |
| #include <string> |
| #include <cerrno> |
| #include <cstdio> |
| #if !defined(_MSC_VER) && !defined(__MINGW32__) |
| #include <unistd.h> |
| #else |
| #include <io.h> |
| #endif |
| #include <fcntl.h> |
| using namespace llvm; |
| |
| // Interface goals: |
| // * StreamableMemoryObject doesn't care about complexities like using |
| // threads/async callbacks to actually overlap download+compile |
| // * Don't want to duplicate Data in memory |
| // * Don't need to know total Data len in advance |
| // Non-goals: |
| // StreamableMemoryObject already has random access so this interface only does |
| // in-order streaming (no arbitrary seeking, else we'd have to buffer all the |
| // Data here in addition to MemoryObject). This also means that if we want |
| // to be able to to free Data, BitstreamBytes/BitcodeReader will implement it |
| |
| STATISTIC(NumStreamFetches, "Number of calls to Data stream fetch"); |
| |
| namespace llvm { |
| DataStreamer::~DataStreamer() {} |
| } |
| |
| namespace { |
| |
| const static error_code success; |
| |
| // Very simple stream backed by a file. Mostly useful for stdin and debugging; |
| // actual file access is probably still best done with mmap. |
| class DataFileStreamer : public DataStreamer { |
| int Fd; |
| public: |
| DataFileStreamer() : Fd(0) {} |
| virtual ~DataFileStreamer() { |
| close(Fd); |
| } |
| virtual size_t GetBytes(unsigned char *buf, size_t len) { |
| NumStreamFetches++; |
| return read(Fd, buf, len); |
| } |
| |
| error_code OpenFile(const std::string &Filename) { |
| int OpenFlags = O_RDONLY; |
| #ifdef O_BINARY |
| OpenFlags |= O_BINARY; // Open input file in binary mode on win32. |
| #endif |
| if (Filename == "-") |
| Fd = 0; |
| else |
| Fd = ::open(Filename.c_str(), OpenFlags); |
| if (Fd == -1) return error_code(errno, posix_category()); |
| return success; |
| } |
| }; |
| |
| } |
| |
| namespace llvm { |
| DataStreamer *getDataFileStreamer(const std::string &Filename, |
| std::string *StrError) { |
| DataFileStreamer *s = new DataFileStreamer(); |
| error_code e = s->OpenFile(Filename); |
| if (e != success) { |
| *StrError = std::string("Could not open ") + Filename + ": " + |
| e.message() + "\n"; |
| return NULL; |
| } |
| return s; |
| } |
| |
| } |