s3_io.h

// MinIO C++ Library for Amazon S3 Compatible Cloud Storage
// Copyright 2021 MinIO, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
 
#ifndef _S3_IO_H
#define _S3_IO_H
 
#include <cstddef>
#include <ostream>
#include <iostream>
#include <sstream>
#include <cstring>
#include <curlpp/Easy.hpp>
 
#include "s3_headers.h"
 
namespace Minio
{
  typedef cURLpp::Easy S3Connection;
        
  // S3ClientIO objects specify data and headers to send,
  // and collect the data and headers of the response.
  struct S3ClientIO {
    std::string httpDate;// Timestamp, set by S3Client::Submit()
    Headers reqHeaders;// Headers for request
    
    std::string result;// Result code for response, minus the leading "HTTP/1.1"
    int numResult;// Numeric result code for response
    Headers respHeaders;// Headers from response
    
    std::ostringstream response;// default output stream, contains body of response
    std::istream * istrm;
    std::ostream * ostrm;
    
    size_t bytesToGet;// used only for progress reporting
    size_t bytesReceived;
    size_t bytesToPut;
    size_t bytesSent;
    
    bool printProgress;
    bool error;
    
    S3ClientIO() {Reset();}
    S3ClientIO(std::istream * i) {Reset(i, NULL);}
    S3ClientIO(std::ostream * o) {Reset(NULL, o);}
    S3ClientIO(std::istream * i, std::ostream * o) {Reset(i, o);}
    
    void Reset(std::istream * i = NULL, std::ostream * o = NULL) {
      reqHeaders.Clear();
      respHeaders.Clear();
      response.clear();
      httpDate = "";
      result = "";
      numResult = 0;
      istrm = NULL;
      ostrm = (o == NULL)? &response : o;
      bytesToGet = 0; bytesReceived = 0;
      bytesToPut = 0; bytesSent = 0;
      printProgress = false;
      error = false;
    }
    
    // "200 OK", or some other 20x message
    bool Success() const {return result[0] == '2' && !error;}
    bool Failure() const {return !Success();}
    
    // Called prior to performing action
    virtual void WillStart();
      
    // Called after action is complete
    virtual void DidFinish();
      
    // Handler for data received by libcurl
    virtual size_t Write(char * buf, size_t size, size_t nmemb);
      
    // Handler for data requested by libcurl for transmission
    virtual size_t Read(char * buf, size_t size, size_t nmemb);
      
    // Handler for headers: overrides must call if other functionality of
    // S3ClientIO is to be used.
    virtual size_t HandleHeader(char * buf, size_t size, size_t nmemb);
      
    friend std::ostream & operator<<(std::ostream & ostrm, S3ClientIO & io);
  };      
}
 
#endif /* _S3_IO_H */