univalue_write.cpp

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// Copyright 2014 BitPay Inc.
// Distributed under the MIT software license, see the accompanying
// file COPYING or https://opensource.org/licenses/mit-license.php.
 
#include <univalue.h>
#include <univalue_escapes.h>
 
#include <cstddef>
#include <string>
#include <utility>
 
namespace {
struct UniValueStreamWriter {
    std::string str;
 
    UniValueStreamWriter() { str.reserve(1024); }
 
    std::string getString() {
#if __cplusplus >= 201103L
        return std::move(str);
#else
        std::string ret;
        std::swap(ret, str);
        return ret;
#endif
    }
 
    void put(char c) { str.push_back(c); }
    void put(char c, size_t nFill) { str.append(nFill, c); }
    void write(const char *s) { str.append(s); }
    void write(const std::string &s) { str.append(s); }
 
    void indentStr(unsigned int prettyIndent, unsigned int indentLevel) {
        put(' ', prettyIndent * indentLevel);
    }
 
    void escapeJson(const std::string &inS);
    void writeAny(unsigned int prettyIndent, unsigned int indentLevel,
                  const UniValue &obj);
    void writeArray(unsigned int prettyIndent, unsigned int indentLevel,
                    const UniValue &obj);
    void writeObject(unsigned int prettyIndent, unsigned int indentLevel,
                     const UniValue &obj);
};
 
void UniValueStreamWriter::escapeJson(const std::string &inS) {
    size_t len = inS.length();
    for (size_t i = 0; i < len; i++) {
        const char ch = inS[i];
        const char *const escStr = escapes[uint8_t(ch)];
 
        if (escStr) {
            write(escStr);
        } else {
            put(ch);
        }
    }
}
 
void UniValueStreamWriter::writeAny(unsigned int prettyIndent,
                                    unsigned int indentLevel,
                                    const UniValue &obj) {
    unsigned int modIndent = indentLevel;
    if (modIndent == 0) {
        modIndent = 1;
    }
 
    switch (obj.typ) {
        case UniValue::VNULL:
            write("null");
            break;
        case UniValue::VOBJ:
            writeObject(prettyIndent, modIndent, obj);
            break;
        case UniValue::VARR:
            writeArray(prettyIndent, modIndent, obj);
            break;
        case UniValue::VSTR:
            put('"');
            escapeJson(obj.val);
            put('"');
            break;
        case UniValue::VNUM:
            write(obj.val);
            break;
        case UniValue::VBOOL:
            write(obj.val == "1" ? "true" : "false");
            break;
    }
}
 
void UniValueStreamWriter::writeArray(unsigned int prettyIndent,
                                      unsigned int indentLevel,
                                      const UniValue &obj) {
    put('[');
    if (prettyIndent) {
        put('\n');
    }
 
    const size_t nValues = obj.values.size();
    for (size_t i = 0; i < nValues; ++i) {
        if (prettyIndent) {
            indentStr(prettyIndent, indentLevel);
        }
        writeAny(prettyIndent, indentLevel + 1, obj.values[i]);
        if (i != nValues - 1) {
            put(',');
        }
        if (prettyIndent) {
            put('\n');
        }
    }
 
    if (prettyIndent) {
        indentStr(prettyIndent, indentLevel - 1);
    }
    put(']');
}
 
void UniValueStreamWriter::writeObject(unsigned int prettyIndent,
                                       unsigned int indentLevel,
                                       const UniValue &obj) {
    put('{');
    if (prettyIndent) {
        put('\n');
    }
 
    // Note: if typ == VOBJ, then keys.size() == values.size() always, so we can
    // use the non-bounds-checking operator[]() for both keys and values here
    // safely.
    const size_t nItems = obj.keys.size();
    for (size_t i = 0; i < nItems; ++i) {
        if (prettyIndent) {
            indentStr(prettyIndent, indentLevel);
        }
        put('"');
        escapeJson(obj.keys[i]);
        write("\":");
 
        if (prettyIndent) {
            put(' ');
        }
        writeAny(prettyIndent, indentLevel + 1, obj.values[i]);
        if (i != nItems - 1) {
            put(',');
        }
        if (prettyIndent) {
            put('\n');
        }
    }
 
    if (prettyIndent) {
        indentStr(prettyIndent, indentLevel - 1);
    }
    put('}');
}
} // namespace
 
std::string UniValue::write(unsigned int prettyIndent,
                            unsigned int indentLevel) const {
    UniValueStreamWriter ss;
    ss.writeAny(prettyIndent, indentLevel, *this);
    return ss.getString();
}