doc_copy_test.cpp

#include <iostream>
#include "rapidjson/document.h"
#include "rapidjson/pointer.h"
#include "rapidjson/stringbuffer.h"
#include "rapidjson/writer.h"

/*
Evaluates the deep copy abilities of rapidjson when operating on an entire document.
Output text should match this:

Raw input:        {"key":"value","array":[5,4,3,2],"nested":{"child":true}}
Original:         {"key":"value","array":[5,4,3,2],"nested":{"child":true}}
Original (again): {"key":"value","array":[5,4,3,2],"nested":{"child":true}}
Copy:             {"key":"!!!ue","array":[5,4,42,2],"nested":{"child":false,"sibling":99.9}}
*/

int main(int argc, char * argv[]) {
    auto input = "{\"key\":\"value\",\"array\":[5,4,3,2],\"nested\":{\"child\":true}}";

    // Print the raw input
    std::cout << "Raw input:        " << input << std::endl;

    rapidjson::Document inDoc;
    inDoc.Parse(input);
    
    // Print the document
    {
        rapidjson::StringBuffer buffer;
        rapidjson::Writer<rapidjson::StringBuffer> writer(buffer);
        inDoc.Accept(writer);
        std::cout << "Original:         " << buffer.GetString() << std::endl;
    }
    
    // Make the copy
    rapidjson::Document outDoc;
    outDoc.CopyFrom(inDoc, outDoc.GetAllocator());
    
    // Modify the copy
    SetValueByPointer(outDoc, "/array/2", 42);
    SetValueByPointer(outDoc, "/nested/child", false);
    SetValueByPointer(outDoc, "/nested/sibling", 99.9);
    
    // Manually modify the string in memory to confirm that the memory is not shared between documents
    rapidjson::Pointer ptr("/key");
    rapidjson::Value* val = ptr.Get(outDoc);
    memcpy(val, "!!!", 3);
    
    // Print the original again
    {
        rapidjson::StringBuffer buffer;
        rapidjson::Writer<rapidjson::StringBuffer> writer(buffer);
        inDoc.Accept(writer);
        std::cout << "Original (again): " << buffer.GetString() << std::endl;
    }

    // Print the copy
    {
        rapidjson::StringBuffer buffer;
        rapidjson::Writer<rapidjson::StringBuffer> writer(buffer);
        outDoc.Accept(writer);
        std::cout << "Copy:             " << buffer.GetString() << std::endl;
    }
}