Implement QPDFArgParser based on ArgParser from qpdf.cc

1 files changed, 799 insertions, 0 deletions

diff --git a/libqpdf/QPDFArgParser.cc b/libqpdf/QPDFArgParser.cc
new file mode 100644
index 00000000..81b6557d
--- /dev/null
+++ b/libqpdf/QPDFArgParser.cc
@@ -0,0 +1,799 @@
+#include <qpdf/QPDFArgParser.hh>
+#include <qpdf/QUtil.hh>
+#include <qpdf/QIntC.hh>
+#include <qpdf/QTC.hh>
+#include <iostream>
+#include <cstring>
+#include <cstdlib>
+
+QPDFArgParser::Usage::Usage(std::string const& msg) :
+    std::runtime_error(msg)
+{
+}
+
+QPDFArgParser::Members::Members(
+    int argc, char* argv[], char const* progname_env) :
+
+    argc(argc),
+    argv(argv),
+    whoami(QUtil::getWhoami(argv[0])),
+    progname_env(progname_env),
+    cur_arg(0),
+    bash_completion(false),
+    zsh_completion(false),
+    option_table(nullptr),
+    final_check_handler(nullptr)
+{
+}
+
+QPDFArgParser::QPDFArgParser(int argc, char* argv[], char const* progname_env) :
+    m(new Members(argc, argv, progname_env))
+{
+    selectHelpOptionTable();
+    addBare("completion-bash",
+            std::bind(std::mem_fn(&QPDFArgParser::argCompletionBash), this));
+    addBare("completion-zsh",
+            std::bind(std::mem_fn(&QPDFArgParser::argCompletionZsh), this));
+    selectMainOptionTable();
+}
+
+void
+QPDFArgParser::selectMainOptionTable()
+{
+    this->m->option_table = &this->m->main_option_table;
+    this->m->option_table_name = "main";
+}
+
+void
+QPDFArgParser::selectHelpOptionTable()
+{
+    this->m->option_table = &this->m->help_option_table;
+    this->m->option_table_name = "help";
+}
+
+void
+QPDFArgParser::selectOptionTable(std::string const& name)
+{
+    auto t = this->m->option_tables.find(name);
+    if (t == this->m->option_tables.end())
+    {
+        QTC::TC("libtests", "QPDFArgParser select unregistered table");
+        throw std::logic_error(
+            "QPDFArgParser: selecting unregistered option table " + name);
+    }
+    this->m->option_table = &(t->second);
+    this->m->option_table_name = name;
+}
+
+void
+QPDFArgParser::registerOptionTable(
+    std::string const& name,
+    bare_arg_handler_t end_handler)
+{
+    if (0 != this->m->option_tables.count(name))
+    {
+        QTC::TC("libtests", "QPDFArgParser register registered table");
+        throw std::logic_error(
+            "QPDFArgParser: registering already registered option table "
+            + name);
+    }
+    this->m->option_tables[name];
+    selectOptionTable(name);
+    addBare("--", end_handler);
+}
+
+QPDFArgParser::OptionEntry&
+QPDFArgParser::registerArg(std::string const& arg)
+{
+    if (0 != this->m->option_table->count(arg))
+    {
+        QTC::TC("libtests", "QPDFArgParser duplicate handler");
+        throw std::logic_error(
+            "QPDFArgParser: adding a duplicate handler for option " +
+            arg + " in " + this->m->option_table_name +
+            " option table");
+    }
+    return ((*this->m->option_table)[arg]);
+}
+
+void
+QPDFArgParser::addPositional(param_arg_handler_t handler)
+{
+    OptionEntry& oe = registerArg("");
+    oe.param_arg_handler = handler;
+}
+
+void
+QPDFArgParser::addBare(
+    std::string const& arg, bare_arg_handler_t handler)
+{
+    OptionEntry& oe = registerArg(arg);
+    oe.parameter_needed = false;
+    oe.bare_arg_handler = handler;
+}
+
+void
+QPDFArgParser::addRequiredParameter(
+    std::string const& arg,
+    param_arg_handler_t handler,
+    char const* parameter_name)
+{
+    OptionEntry& oe = registerArg(arg);
+    oe.parameter_needed = true;
+    oe.parameter_name = parameter_name;
+    oe.param_arg_handler = handler;
+}
+
+void
+QPDFArgParser::addOptionalParameter(
+    std::string const& arg, param_arg_handler_t handler)
+{
+    OptionEntry& oe = registerArg(arg);
+    oe.parameter_needed = false;
+    oe.param_arg_handler = handler;
+}
+
+void
+QPDFArgParser::addRequiredChoices(
+    std::string const& arg,
+    param_arg_handler_t handler,
+    char const** choices)
+{
+    OptionEntry& oe = registerArg(arg);
+    oe.parameter_needed = true;
+    oe.param_arg_handler = handler;
+    for (char const** i = choices; *i; ++i)
+    {
+        oe.choices.insert(*i);
+    }
+}
+
+void
+QPDFArgParser::addFinalCheck(bare_arg_handler_t handler)
+{
+    this->m->final_check_handler = handler;
+}
+
+bool
+QPDFArgParser::isCompleting() const
+{
+    return this->m->bash_completion;
+}
+
+int
+QPDFArgParser::argsLeft() const
+{
+    return this->m->argc - this->m->cur_arg - 1;
+}
+
+void
+QPDFArgParser::insertCompletion(std::string const& arg)
+{
+    this->m->completions.insert(arg);
+}
+
+void
+QPDFArgParser::completionCommon(bool zsh)
+{
+    std::string progname = this->m->argv[0];
+    std::string executable;
+    std::string appdir;
+    std::string appimage;
+    if (QUtil::get_env(this->m->progname_env.c_str(), &executable))
+    {
+        progname = executable;
+    }
+    else if (QUtil::get_env("APPDIR", &appdir) &&
+             QUtil::get_env("APPIMAGE", &appimage))
+    {
+        // Detect if we're in an AppImage and adjust
+        if ((appdir.length() < strlen(this->m->argv[0])) &&
+            (strncmp(appdir.c_str(), this->m->argv[0], appdir.length()) == 0))
+        {
+            progname = appimage;
+        }
+    }
+    if (zsh)
+    {
+        std::cout << "autoload -U +X bashcompinit && bashcompinit && ";
+    }
+    std::cout << "complete -o bashdefault -o default";
+    if (! zsh)
+    {
+        std::cout << " -o nospace";
+    }
+    std::cout << " -C " << progname << " " << this->m->whoami << std::endl;
+    // Put output before error so calling from zsh works properly
+    std::string path = progname;
+    size_t slash = path.find('/');
+    if ((slash != 0) && (slash != std::string::npos))
+    {
+        std::cerr << "WARNING: " << this->m->whoami << " completion enabled"
+                  << " using relative path to executable" << std::endl;
+    }
+}
+
+void
+QPDFArgParser::argCompletionBash()
+{
+    completionCommon(false);
+}
+
+void
+QPDFArgParser::argCompletionZsh()
+{
+    completionCommon(true);
+}
+
+void
+QPDFArgParser::handleArgFileArguments()
+{
+    // Support reading arguments from files. Create a new argv. Ensure
+    // that argv itself as well as all its contents are automatically
+    // deleted by using PointerHolder objects to back the pointers in
+    // argv.
+    this->m->new_argv.push_back(
+        PointerHolder<char>(true, QUtil::copy_string(this->m->argv[0])));
+    for (int i = 1; i < this->m->argc; ++i)
+    {
+        char* argfile = 0;
+        if ((strlen(this->m->argv[i]) > 1) && (this->m->argv[i][0] == '@'))
+        {
+            argfile = 1 + this->m->argv[i];
+            if (strcmp(argfile, "-") != 0)
+            {
+                if (! QUtil::file_can_be_opened(argfile))
+                {
+                    // The file's not there; treating as regular option
+                    argfile = nullptr;
+                }
+            }
+        }
+        if (argfile)
+        {
+            readArgsFromFile(1 + this->m->argv[i]);
+        }
+        else
+        {
+            this->m->new_argv.push_back(
+                PointerHolder<char>(
+                    true, QUtil::copy_string(this->m->argv[i])));
+        }
+    }
+    this->m->argv_ph =
+        PointerHolder<char*>(true, new char*[1 + this->m->new_argv.size()]);
+    this->m->argv = this->m->argv_ph.getPointer();
+    for (size_t i = 0; i < this->m->new_argv.size(); ++i)
+    {
+        this->m->argv[i] = this->m->new_argv.at(i).getPointer();
+    }
+    this->m->argc = QIntC::to_int(this->m->new_argv.size());
+    this->m->argv[this->m->argc] = 0;
+}
+
+void
+QPDFArgParser::handleBashArguments()
+{
+    // Do a minimal job of parsing bash_line into arguments. This
+    // doesn't do everything the shell does (e.g. $(...), variable
+    // expansion, arithmetic, globs, etc.), but it should be good
+    // enough for purposes of handling completion. As we build up the
+    // new argv, we can't use this->m->new_argv because this code has to
+    // interoperate with @file arguments, so memory for both ways of
+    // fabricating argv has to be protected.
+
+    bool last_was_backslash = false;
+    enum { st_top, st_squote, st_dquote } state = st_top;
+    std::string arg;
+    for (std::string::iterator iter = this->m->bash_line.begin();
+         iter != this->m->bash_line.end(); ++iter)
+    {
+        char ch = (*iter);
+        if (last_was_backslash)
+        {
+            arg.append(1, ch);
+            last_was_backslash = false;
+        }
+        else if (ch == '\\')
+        {
+            last_was_backslash = true;
+        }
+        else
+        {
+            bool append = false;
+            switch (state)
+            {
+              case st_top:
+                if (QUtil::is_space(ch))
+                {
+                    if (! arg.empty())
+                    {
+                        this->m->bash_argv.push_back(
+                            PointerHolder<char>(
+                                true, QUtil::copy_string(arg.c_str())));
+                        arg.clear();
+                    }
+                }
+                else if (ch == '"')
+                {
+                    state = st_dquote;
+                }
+                else if (ch == '\'')
+                {
+                    state = st_squote;
+                }
+                else
+                {
+                    append = true;
+                }
+                break;
+
+              case st_squote:
+                if (ch == '\'')
+                {
+                    state = st_top;
+                }
+                else
+                {
+                    append = true;
+                }
+                break;
+
+              case st_dquote:
+                if (ch == '"')
+                {
+                    state = st_top;
+                }
+                else
+                {
+                    append = true;
+                }
+                break;
+            }
+            if (append)
+            {
+                arg.append(1, ch);
+            }
+        }
+    }
+    if (this->m->bash_argv.empty())
+    {
+        // This can't happen if properly invoked by bash, but ensure
+        // we have a valid argv[0] regardless.
+        this->m->bash_argv.push_back(
+            PointerHolder<char>(
+                true, QUtil::copy_string(this->m->argv[0])));
+    }
+    // Explicitly discard any non-space-terminated word. The "current
+    // word" is handled specially.
+    this->m->bash_argv_ph =
+        PointerHolder<char*>(true, new char*[1 + this->m->bash_argv.size()]);
+    this->m->argv = this->m->bash_argv_ph.getPointer();
+    for (size_t i = 0; i < this->m->bash_argv.size(); ++i)
+    {
+        this->m->argv[i] = this->m->bash_argv.at(i).getPointer();
+    }
+    this->m->argc = QIntC::to_int(this->m->bash_argv.size());
+    this->m->argv[this->m->argc] = 0;
+}
+
+void
+QPDFArgParser::usage(std::string const& message)
+{
+    if (this->m->bash_completion)
+    {
+        // This will cause bash to fall back to regular file completion.
+        exit(0);
+    }
+    throw Usage(message);
+}
+
+void
+QPDFArgParser::readArgsFromFile(char const* filename)
+{
+    std::list<std::string> lines;
+    if (strcmp(filename, "-") == 0)
+    {
+        QTC::TC("libtests", "QPDFArgParser read args from stdin");
+        lines = QUtil::read_lines_from_file(std::cin);
+    }
+    else
+    {
+        QTC::TC("libtests", "QPDFArgParser read args from file");
+        lines = QUtil::read_lines_from_file(filename);
+    }
+    for (std::list<std::string>::iterator iter = lines.begin();
+         iter != lines.end(); ++iter)
+    {
+        this->m->new_argv.push_back(
+            PointerHolder<char>(true, QUtil::copy_string((*iter).c_str())));
+    }
+}
+
+void
+QPDFArgParser::checkCompletion()
+{
+    // See if we're being invoked from bash completion.
+    std::string bash_point_env;
+    // On Windows with mingw, there have been times when there appears
+    // to be no way to distinguish between an empty environment
+    // variable and an unset variable. There are also conditions under
+    // which bash doesn't set COMP_LINE. Therefore, enter this logic
+    // if either COMP_LINE or COMP_POINT are set. They will both be
+    // set together under ordinary circumstances.
+    bool got_line = QUtil::get_env("COMP_LINE", &this->m->bash_line);
+    bool got_point = QUtil::get_env("COMP_POINT", &bash_point_env);
+    if (got_line || got_point)
+    {
+        size_t p = QUtil::string_to_uint(bash_point_env.c_str());
+        if (p < this->m->bash_line.length())
+        {
+            // Truncate the line. We ignore everything at or after the
+            // cursor for completion purposes.
+            this->m->bash_line = this->m->bash_line.substr(0, p);
+        }
+        if (p > this->m->bash_line.length())
+        {
+            p = this->m->bash_line.length();
+        }
+        // Set bash_cur and bash_prev based on bash_line rather than
+        // relying on argv. This enables us to use bashcompinit to get
+        // completion in zsh too since bashcompinit sets COMP_LINE and
+        // COMP_POINT but doesn't invoke the command with options like
+        // bash does.
+
+        // p is equal to length of the string. Walk backwards looking
+        // for the first separator. bash_cur is everything after the
+        // last separator, possibly empty.
+        char sep(0);
+        while (p > 0)
+        {
+            --p;
+            char ch = this->m->bash_line.at(p);
+            if ((ch == ' ') || (ch == '=') || (ch == ':'))
+            {
+                sep = ch;
+                break;
+            }
+        }
+        if (1+p <= this->m->bash_line.length())
+        {
+            this->m->bash_cur = this->m->bash_line.substr(
+                1+p, std::string::npos);
+        }
+        if ((sep == ':') || (sep == '='))
+        {
+            // Bash sets prev to the non-space separator if any.
+            // Actually, if there are multiple separators in a row,
+            // they are all included in prev, but that detail is not
+            // important to us and not worth coding.
+            this->m->bash_prev = this->m->bash_line.substr(p, 1);
+        }
+        else
+        {
+            // Go back to the last separator and set prev based on
+            // that.
+            size_t p1 = p;
+            while (p1 > 0)
+            {
+                --p1;
+                char ch = this->m->bash_line.at(p1);
+                if ((ch == ' ') || (ch == ':') || (ch == '='))
+                {
+                    this->m->bash_prev =
+                        this->m->bash_line.substr(p1 + 1, p - p1 - 1);
+                    break;
+                }
+            }
+        }
+        if (this->m->bash_prev.empty())
+        {
+            this->m->bash_prev = this->m->bash_line.substr(0, p);
+        }
+        if (this->m->argc == 1)
+        {
+            // This is probably zsh using bashcompinit. There are a
+            // few differences in the expected output.
+            this->m->zsh_completion = true;
+        }
+        handleBashArguments();
+        this->m->bash_completion = true;
+    }
+}
+
+void
+QPDFArgParser::parseArgs()
+{
+    selectMainOptionTable();
+    checkCompletion();
+    handleArgFileArguments();
+    for (this->m->cur_arg = 1;
+         this->m->cur_arg < this->m->argc;
+         ++this->m->cur_arg)
+    {
+        bool help_option = false;
+        bool end_option = false;
+        auto oep = this->m->option_table->end();
+        char* arg = this->m->argv[this->m->cur_arg];
+        char* parameter = nullptr;
+        std::string o_arg(arg);
+        std::string arg_s(arg);
+        if ((strcmp(arg, "--") == 0) &&
+            (this->m->option_table != &this->m->main_option_table))
+        {
+            // Special case for -- option, which is used to break out
+            // of subparsers.
+            oep = this->m->option_table->find("--");
+            end_option = true;
+            if (oep == this->m->option_table->end())
+            {
+                // This is registered automatically, so this can't happen.
+                throw std::logic_error("ArgParser: -- handler not registered");
+            }
+        }
+        else if ((arg[0] == '-') && (strcmp(arg, "-") != 0))
+        {
+            ++arg;
+            if (arg[0] == '-')
+            {
+                // Be lax about -arg vs --arg
+                ++arg;
+            }
+            else
+            {
+                QTC::TC("libtests", "QPDFArgParser single dash");
+            }
+            if (strlen(arg) > 0)
+            {
+                // Prevent --=something from being treated as an empty
+                // arg since the empty string in the option table is
+                // for positional arguments.
+                parameter = const_cast<char*>(strchr(1 + arg, '='));
+            }
+            if (parameter)
+            {
+                *parameter++ = 0;
+            }
+
+            arg_s = arg;
+
+            if ((! this->m->bash_completion) &&
+                (this->m->argc == 2) && (this->m->cur_arg == 1) &&
+                this->m->help_option_table.count(arg_s))
+            {
+                // Handle help option, which is only valid as the sole
+                // option.
+                QTC::TC("libtests", "QPDFArgParser help option");
+                oep = this->m->help_option_table.find(arg_s);
+                help_option = true;
+            }
+
+            if (! (help_option || arg_s.empty() || (arg_s.at(0) == '-')))
+            {
+                oep = this->m->option_table->find(arg_s);
+            }
+        }
+        else
+        {
+            // The empty string maps to the positional argument
+            // handler.
+            QTC::TC("libtests", "QPDFArgParser positional");
+            oep = this->m->option_table->find("");
+            parameter = arg;
+        }
+
+        if (oep == this->m->option_table->end())
+        {
+            QTC::TC("libtests", "QPDFArgParser unrecognized");
+            std::string message = "unrecognized argument " + o_arg;
+            if (this->m->option_table != &this->m->main_option_table)
+            {
+                message += " (" + this->m->option_table_name +
+                    " options must be terminated with --)";
+            }
+            usage(message);
+        }
+
+        OptionEntry& oe = oep->second;
+        if ((oe.parameter_needed && (0 == parameter)) ||
+            ((! oe.choices.empty() &&
+              ((0 == parameter) ||
+               (0 == oe.choices.count(parameter))))))
+        {
+            std::string message =
+                "--" + arg_s + " must be given as --" + arg_s + "=";
+            if (! oe.choices.empty())
+            {
+                QTC::TC("libtests", "QPDFArgParser required choices");
+                message += "{";
+                for (std::set<std::string>::iterator iter =
+                         oe.choices.begin();
+                     iter != oe.choices.end(); ++iter)
+                {
+                    if (iter != oe.choices.begin())
+                    {
+                        message += ",";
+                    }
+                    message += *iter;
+                }
+                message += "}";
+            }
+            else if (! oe.parameter_name.empty())
+            {
+                QTC::TC("libtests", "QPDFArgParser required parameter");
+                message += oe.parameter_name;
+            }
+            else
+            {
+                // should not be possible
+                message += "option";
+            }
+            usage(message);
+        }
+        if (oe.bare_arg_handler)
+        {
+            oe.bare_arg_handler();
+        }
+        else if (oe.param_arg_handler)
+        {
+            oe.param_arg_handler(parameter);
+        }
+        if (help_option)
+        {
+            exit(0);
+        }
+        if (end_option)
+        {
+            selectMainOptionTable();
+        }
+    }
+    if (this->m->bash_completion)
+    {
+        handleCompletion();
+    }
+    else
+    {
+        doFinalChecks();
+    }
+}
+
+void
+QPDFArgParser::doFinalChecks()
+{
+    if (this->m->option_table != &(this->m->main_option_table))
+    {
+        QTC::TC("libtests", "QPDFArgParser missing --");
+        usage("missing -- at end of " + this->m->option_table_name +
+              " options");
+    }
+    if (this->m->final_check_handler != nullptr)
+    {
+        this->m->final_check_handler();
+    }
+}
+
+void
+QPDFArgParser::addChoicesToCompletions(std::string const& option,
+                                       std::string const& extra_prefix)
+{
+    if (this->m->option_table->count(option) != 0)
+    {
+        OptionEntry& oe = (*this->m->option_table)[option];
+        for (std::set<std::string>::iterator iter = oe.choices.begin();
+             iter != oe.choices.end(); ++iter)
+        {
+            QTC::TC("libtests", "QPDFArgParser complete choices");
+            this->m->completions.insert(extra_prefix + *iter);
+        }
+    }
+}
+
+void
+QPDFArgParser::addOptionsToCompletions()
+{
+    for (std::map<std::string, OptionEntry>::iterator iter =
+             this->m->option_table->begin();
+         iter != this->m->option_table->end(); ++iter)
+    {
+        std::string const& arg = (*iter).first;
+        if (arg == "--")
+        {
+            continue;
+        }
+        OptionEntry& oe = (*iter).second;
+        std::string base = "--" + arg;
+        if (oe.param_arg_handler)
+        {
+            if (this->m->zsh_completion)
+            {
+                // zsh doesn't treat = as a word separator, so add all
+                // the options so we don't get a space after the =.
+                addChoicesToCompletions(arg, base + "=");
+            }
+            this->m->completions.insert(base + "=");
+        }
+        if (! oe.parameter_needed)
+        {
+            this->m->completions.insert(base);
+        }
+    }
+}
+
+void
+QPDFArgParser::handleCompletion()
+{
+    std::string extra_prefix;
+    if (this->m->completions.empty())
+    {
+        // Detect --option=... Bash treats the = as a word separator.
+        std::string choice_option;
+        if (this->m->bash_cur.empty() && (this->m->bash_prev.length() > 2) &&
+            (this->m->bash_prev.at(0) == '-') &&
+            (this->m->bash_prev.at(1) == '-') &&
+            (this->m->bash_line.at(this->m->bash_line.length() - 1) == '='))
+        {
+            choice_option = this->m->bash_prev.substr(2, std::string::npos);
+        }
+        else if ((this->m->bash_prev == "=") &&
+                 (this->m->bash_line.length() >
+                  (this->m->bash_cur.length() + 1)))
+        {
+            // We're sitting at --option=x. Find previous option.
+            size_t end_mark = this->m->bash_line.length() -
+                this->m->bash_cur.length() - 1;
+            char before_cur = this->m->bash_line.at(end_mark);
+            if (before_cur == '=')
+            {
+                size_t space = this->m->bash_line.find_last_of(' ', end_mark);
+                if (space != std::string::npos)
+                {
+                    std::string candidate =
+                        this->m->bash_line.substr(
+                            space + 1, end_mark - space - 1);
+                    if ((candidate.length() > 2) &&
+                        (candidate.at(0) == '-') &&
+                        (candidate.at(1) == '-'))
+                    {
+                        choice_option =
+                            candidate.substr(2, std::string::npos);
+                    }
+                }
+            }
+        }
+        if (! choice_option.empty())
+        {
+            if (this->m->zsh_completion)
+            {
+                // zsh wants --option=choice rather than just choice
+                extra_prefix = "--" + choice_option + "=";
+            }
+            addChoicesToCompletions(choice_option, extra_prefix);
+        }
+        else if ((! this->m->bash_cur.empty()) &&
+                 (this->m->bash_cur.at(0) == '-'))
+        {
+            addOptionsToCompletions();
+            if (this->m->argc == 1)
+            {
+                // Help options are valid only by themselves.
+                for (std::map<std::string, OptionEntry>::iterator iter =
+                         this->m->help_option_table.begin();
+                     iter != this->m->help_option_table.end(); ++iter)
+                {
+                    this->m->completions.insert("--" + (*iter).first);
+                }
+            }
+        }
+    }
+    std::string prefix = extra_prefix + this->m->bash_cur;
+    for (std::set<std::string>::iterator iter = this->m->completions.begin();
+         iter != this->m->completions.end(); ++iter)
+    {
+        if (prefix.empty() ||
+            ((*iter).substr(0, prefix.length()) == prefix))
+        {
+            std::cout << *iter << std::endl;
+        }
+    }
+    exit(0);
+}