AdhocCliCommParser.cc

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#include "AdhocCliCommParser.hh"
#include "utf8_unchecked.hh"
#include "xrange.hh"
 
 
AdhocCliCommParser::AdhocCliCommParser(std::function<void(const std::string&)> callback_)
        : callback(std::move(callback_))
{
}
 
void AdhocCliCommParser::parse(std::span<const char> buf)
{
        for (auto c : buf) {
                parse(c);
        }
}
 
void AdhocCliCommParser::parse(char c)
{
        // Whenever there is a parse error we return to the initial state
        switch (state) {
        case O0: // looking for opening tag
                state = (c == '<') ? O1 : O0; break;
        case O1: // matched <
                state = (c == 'c') ? O2 : O0; break;
        case O2: // matched <c
                state = (c == 'o') ? O3 : O0; break;
        case O3: // matched <co
                state = (c == 'm') ? O4 : O0; break;
        case O4: // matched <com
                state = (c == 'm') ? O5 : O0; break;
        case O5: // matched <comm
                state = (c == 'a') ? O6 : O0; break;
        case O6: // matched <comma
                state = (c == 'n') ? O7 : O0; break;
        case O7: // matched <comman
                state = (c == 'd') ? O8 : O0; break;
        case O8: // matched <command
                if (c == '>') {
                        state = C0;
                        command.clear();
                } else {
                        state = O0;
                }
                break;
        case C0: // matched <command>, now parsing xml entities and </command>
                if      (c == '<') state = C1;
                else if (c == '&') state = A1;
                else command += c;
                break;
        case C1: // matched <
                state = (c == '/') ? C2 : O0; break;
        case C2: // matched </
                state = (c == 'c') ? C3 : O0; break;
        case C3: // matched </c
                state = (c == 'o') ? C4 : O0; break;
        case C4: // matched </co
                state = (c == 'm') ? C5 : O0; break;
        case C5: // matched </com
                state = (c == 'm') ? C6 : O0; break;
        case C6: // matched </comm
                state = (c == 'a') ? C7 : O0; break;
        case C7: // matched </comma
                state = (c == 'n') ? C8 : O0; break;
        case C8: // matched </comman
                state = (c == 'd') ? C9 : O0; break;
        case C9: // matched </command
                if (c == '>') callback(command);
                state = O0;
                break;
        case A1: // matched &
                if      (c == 'l') state = L2;
                else if (c == 'a') state = A2;
                else if (c == 'g') state = G2;
                else if (c == 'q') state = Q2;
                else if (c == '#') { state = H2; unicode = 0; }
                else               state = O0; // error
                break;
        case A2: // matched &a
                if      (c == 'm') state = A3;
                else if (c == 'p') state = P3;
                else               state = O0; // error
                break;
        case A3: // matched &am
                state = (c == 'p') ? A4 : O0; break;
        case A4: // matched &amp
                if (c == ';') {
                        command += '&';
                        state = C0;
                } else {
                        state = O0; // error
                }
                break;
        case P3: // matched &ap
                state = (c == 'o') ? P4 : O0; break;
        case P4: // matched &apo
                state = (c == 's') ? P5 : O0; break;
        case P5: // matched &apos
                if (c == ';') {
                        command += '\'';
                        state = C0;
                } else {
                        state = O0; // error
                }
                break;
        case Q2: // matched &q
                state = (c == 'u') ? Q3 : O0; break;
        case Q3: // matched &qu
                state = (c == 'o') ? Q4 : O0; break;
        case Q4: // matched &quo
                state = (c == 't') ? Q5 : O0; break;
        case Q5: // matched &quot
                if (c == ';') {
                        command += '"';
                        state = C0;
                } else {
                        state = O0; // error
                }
                break;
        case G2: // matched &g
                state = (c == 't') ? G3 : O0; break;
        case G3: // matched &gt
                if (c == ';') {
                        command += '>';
                        state = C0;
                } else {
                        state = O0; // error
                }
                break;
        case L2: // matched &l
                state = (c == 't') ? L3 : O0; break;
        case L3: // matched &lt
                if (c == ';') {
                        command += '<';
                        state = C0;
                } else {
                        state = O0; // error
                }
                break;
        case H2: // matched &#
                // This also parses invalid input like '&#12xab;' but let's
                // ignore that. It also doesn't check for overflow etc.
                if (c == ';') {
                        utf8::unchecked::append(unicode, back_inserter(command));
                        state = C0;
                } else if (c == 'x') {
                        state = H3;
                } else {
                        unicode *= 10;
                        if (('0' <= c) && (c <= '9')) unicode += c - '0';
                        else state = O0;
                }
                break;
        case H3: // matched &#x
                if (c == ';') {
                        utf8::unchecked::append(unicode, back_inserter(command));
                        state = C0;
                } else {
                        unicode *= 16;
                        if      (('0' <= c) && (c <= '9')) unicode += c - '0';
                        else if (('a' <= c) && (c <= 'f')) unicode += c - 'a' + 10;
                        else if (('A' <= c) && (c <= 'F')) unicode += c - 'A' + 10;
                        else state = O0;
                }
                break;
        }
}