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#include "Parser.h"
#include <stdio.h>
#include <unistd.h>
void Parser::commit_token()
{
if (m_token.is_empty())
return;
if (m_state == InRedirectionPath) {
m_redirections.last().path = String::copy(m_token);
m_token.clear_with_capacity();
return;
}
m_tokens.append(String::copy(m_token));
m_token.clear_with_capacity();
};
void Parser::commit_subcommand()
{
if (m_tokens.is_empty())
return;
m_subcommands.append({ move(m_tokens), move(m_redirections), {} });
}
void Parser::do_pipe()
{
m_redirections.append({ Redirection::Pipe, STDOUT_FILENO });
commit_subcommand();
}
void Parser::begin_redirect_read(int fd)
{
m_redirections.append({ Redirection::FileRead, fd });
}
void Parser::begin_redirect_write(int fd)
{
m_redirections.append({ Redirection::FileWrite, fd });
}
Vector<Subcommand> Parser::parse()
{
for (int i = 0; i < m_input.length(); ++i) {
char ch = m_input.characters()[i];
switch (m_state) {
case State::Free:
if (ch == ' ') {
commit_token();
break;
}
if (ch == '|') {
commit_token();
if (m_tokens.is_empty()) {
fprintf(stderr, "Syntax error: Nothing before pipe (|)\n");
return {};
}
do_pipe();
break;
}
if (ch == '>') {
commit_token();
begin_redirect_write(STDOUT_FILENO);
// Search for another > for append.
m_state = State::InWriteAppendOrRedirectionPath;
break;
}
if (ch == '<') {
commit_token();
begin_redirect_read(STDIN_FILENO);
m_state = State::InRedirectionPath;
break;
}
if (ch == '\'') {
m_state = State::InSingleQuotes;
break;
}
if (ch == '\"') {
m_state = State::InDoubleQuotes;
break;
}
m_token.append(ch);
break;
case State::InWriteAppendOrRedirectionPath:
if (ch == '>') {
commit_token();
m_state = State::InRedirectionPath;
ASSERT(m_redirections.size());
m_redirections[m_redirections.size() - 1].type = Redirection::FileWriteAppend;
break;
}
// Not another > means that it's probably a path.
m_state = InRedirectionPath;
[[fallthrough]];
case State::InRedirectionPath:
if (ch == '<') {
commit_token();
begin_redirect_read(STDIN_FILENO);
m_state = State::InRedirectionPath;
break;
}
if (ch == '>') {
commit_token();
begin_redirect_read(STDOUT_FILENO);
m_state = State::InRedirectionPath;
break;
}
if (ch == '|') {
commit_token();
if (m_tokens.is_empty()) {
fprintf(stderr, "Syntax error: Nothing before pipe (|)\n");
return {};
}
do_pipe();
m_state = State::Free;
break;
}
if (ch == ' ')
break;
m_token.append(ch);
break;
case State::InSingleQuotes:
if (ch == '\'') {
commit_token();
m_state = State::Free;
break;
}
m_token.append(ch);
break;
case State::InDoubleQuotes:
if (ch == '\"') {
commit_token();
m_state = State::Free;
break;
}
m_token.append(ch);
break;
};
}
commit_token();
commit_subcommand();
if (!m_subcommands.is_empty()) {
for (auto& redirection : m_subcommands.last().redirections) {
if (redirection.type == Redirection::Pipe) {
fprintf(stderr, "Syntax error: Nothing after last pipe (|)\n");
return {};
}
}
}
return move(m_subcommands);
}
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