FileCommands.hxx

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#ifndef _CONSOLE_FILECOMMANDS_HXX_
#define _CONSOLE_FILECOMMANDS_HXX_
 
#include <dirent.h>
 
#include "console/Console.hxx"
 
class FileCommands
{
public:
    FileCommands(Console *console)
    {
        console->add_command("cat", cat_command);
        console->add_command("echo", echo_command);
        console->add_command("rm", rm_command);
        console->add_command("ls", ls_command);
    }
 
private:
 
    static Console::CommandStatus cat_command(FILE *fp, int argc,
                                              const char *argv[], void *context)
    {
        if (argc == 0)
        {
            fprintf(fp, "concatenate files and print on the standard output\n");
            return Console::COMMAND_OK;
        }
 
        for (int i = 1; i < argc; ++i)
        {
            int fd = ::open(argv[i], O_RDONLY | O_NONBLOCK);
            if (fd < 0)
            {
                fprintf(fp, "%s: %s: No such file or directory\n",
                        argv[0], argv[i]);
                continue;
            }
            ssize_t result;
            do
            {
                char buf[32];
                result = ::read(fd, buf, sizeof(buf));
                if (result > 0)
                {
                    fprintf(fp, "%.*s", result, buf);
                }
            } while (result > 0);
 
            close(fd);
 
            fprintf(fp, "\n");
        }
 
        return Console::COMMAND_OK;
    }
 
    static Console::CommandStatus echo_command(FILE *fp, int argc,
                                               const char *argv[],
                                               void *context)
    {
        if (argc == 0)
        {
            fprintf(fp, "display a line of text\n");
            return Console::COMMAND_OK;
        }
 
        if (argc == 2)
        {
            fprintf(fp, "%s\n", argv[1]);
            return Console::COMMAND_OK;
        }
        else if (argc == 4)
        {
            if (!strcmp(argv[2], ">"))
            {
                int fd = ::open(argv[3], O_WRONLY | O_CREAT);
                if (fd < 0)
                {
                    fprintf(fp, "%s: No such file or directory\n", argv[3]);
                }
                else
                {
                    ssize_t wr_size = strlen(argv[1]);
                    ssize_t result = ::write(fd, argv[1], wr_size);
                    close(fd);
                    return result == wr_size ? Console::COMMAND_OK :
                                               Console::COMMAND_ERROR;
                }
            }
        }
 
        return Console::COMMAND_ERROR;
    }
 
    static Console::CommandStatus rm_command(FILE *fp, int argc,
                                             const char *argv[], void *context)
    {
        if (argc == 0)
        {
            fprintf(fp, "remove files or directories\n");
            return Console::COMMAND_OK;
        }
 
        if (argc < 2)
        {
            return Console::COMMAND_ERROR;
        }
 
        for (int i = 1; i < argc; ++i)
        {
            if (::unlink(argv[i]) == 0)
            {
                continue;
            }
            if (errno == ENOENT)
            {
                fprintf(fp,
                        "%s: cannot remove '%s': No such file or directory\n",
                        argv[0], argv[i]);
            }
        }
 
        return Console::COMMAND_OK;
    }
 
    static Console::CommandStatus ls_command(FILE *fp, int argc,
                                             const char *argv[], void *context)
    {
        if (argc == 0)
        {
            fprintf(fp, "list directory contents\n");
            return Console::COMMAND_OK;
        }
 
        if (argc != 2)
        {
            return Console::COMMAND_ERROR;
        }
 
        struct stat stat;
        if (::stat(argv[1], &stat) != 0)
        {
            if (errno == ENOENT)
            {
                fprintf(fp,
                        "%s: cannot access '%s': No such file or directory\n",
                        argv[0], argv[1]);
            }
            return Console::COMMAND_ERROR;
        }
 
        if (S_ISDIR(stat.st_mode))
        {
            DIR *dir = opendir(argv[1]);
            HASSERT(dir);
            struct dirent *dirent;
            do
            {
                dirent = readdir(dir);
                if (dirent)
                {
                    HASSERT(::stat(dirent->d_name, &stat) == 0);
                    ls_printline(fp, dirent->d_name, &stat);
                }
            } while (dirent);
            closedir(dir);
        }
        else if (S_ISREG(stat.st_mode) || S_ISLNK(stat.st_mode))
        {
            ls_printline(fp, argv[1], &stat);
        }
 
        return Console::COMMAND_OK;
    }
 
    static void ls_printline(FILE *fp, const char *name, struct stat *stat)
    {
        char type;
        type = S_ISDIR(stat->st_mode) ? 'd' : '-';
        type = S_ISLNK(stat->st_mode) ? 'l' : type;
 
        fprintf(fp, "%c%c%c%c%c%c%c%c%c%c %5ld %s\n", type,
                stat->st_mode & S_IRUSR ? 'r' : '-',
                stat->st_mode & S_IWUSR ? 'w' : '-',
                stat->st_mode & S_IXUSR ? 'x' : '-',
                stat->st_mode & S_IRGRP ? 'r' : '-',
                stat->st_mode & S_IWGRP ? 'w' : '-',
                stat->st_mode & S_IXGRP ? 'x' : '-',
                stat->st_mode & S_IROTH ? 'r' : '-',
                stat->st_mode & S_IWOTH ? 'w' : '-',
                stat->st_mode & S_IXOTH ? 'x' : '-',
                stat->st_size, name);
    }
 
    DISALLOW_COPY_AND_ASSIGN(FileCommands);
};
 
#endif // _CONSOLE_FILECOMMANDS_HXX_