[nmh] / uip / scansbr.c

/*
 * scansbr.c -- routines to help scan along...
 *
 * This code is Copyright (c) 2002, by the authors of nmh.  See the
 * COPYRIGHT file in the root directory of the nmh distribution for
 * complete copyright information.
 */

#include <h/mh.h>
#include <h/addrsbr.h>
#include <h/fmt_scan.h>
#include <h/scansbr.h>
#include <h/tws.h>
#include <h/utils.h>

/*
 * Buffer size for content part of header fields.  We want this
 * to be large enough so that we don't do a lot of extra FLDPLUS
 * calls on m_getfld but small enough so that we don't snarf
 * the entire message body when we're only going to display 30
 * characters of it.
 */
#define SBUFSIZ 512

static struct format *fmt;
static struct comp *datecomp;           /* pntr to "date" comp             */
static struct comp *bodycomp;           /* pntr to "body" pseudo-comp      *
                                         * (if referenced)                 */
static int ncomps = 0;                  /* # of interesting components     */
static char **compbuffers = 0;          /* buffers for component text      */
static struct comp **used_buf = 0;      /* stack for comp that use buffers */

static int dat[5];                      /* aux. data for format routine    */

static m_getfld_state_t gstate;         /* for accessor functions below    */

#define DIEWRERR() adios (scnmsg, "write error on")

#define FPUTS(buf) {\
                if (fputs(buf,scnout) == EOF)\
                    DIEWRERR();\
                }

int
scan (FILE *inb, int innum, int outnum, char *nfs, int width, int curflg,
      int unseen, char *folder, long size, int noisy, charstring_t *scanl)
{
    int i, compnum, encrypted, state;
    char *cp, *tmpbuf, *startbody, **nxtbuf;
    char *saved_c_text = NULL;
    struct comp *cptr;
    struct comp **savecomp;
    char *scnmsg = NULL;
    FILE *scnout = NULL;
    char name[NAMESZ];
    int bufsz;
    static int rlwidth, slwidth;

    /* first-time only initialization, which will always happen the
       way the code is now, with callers initializing *scanl to NULL.
       scanl used to be a global. */
    if (! *scanl) {
        if (width == -1) {
            /* Default:  width of the terminal, but at least WIDTH/2. */
            if ((width = sc_width ()) < WIDTH/2)
                width = WIDTH/2;
        } else if (width == 0) {
            /* Unlimited width. */
            width = INT_MAX;
        }
        dat[3] = slwidth = width;
        *scanl = charstring_create (width < NMH_BUFSIZ ? width : NMH_BUFSIZ);
        if (outnum)
            umask(~m_gmprot());

        /* Compile format string */
        ncomps = fmt_compile (nfs, &fmt, 1) + 2;

        bodycomp = fmt_findcomp("body");
        datecomp = fmt_findcomp("date");
        cptr = fmt_findcomp("folder");
        if (cptr && folder)
            cptr->c_text = mh_xstrdup(folder);
        if (fmt_addcompentry("encrypted")) {
                ncomps++;
        }
        cptr =  fmt_findcomp("dtimenow");
        if (cptr)
            cptr->c_text = getcpy(dtimenow (0));

        /*
         * In other programs I got rid of this complicated buffer switching,
         * but since scan reads lots of messages at once and this complicated
         * memory management, I decided to keep it; otherwise there was
         * the potential for a lot of malloc() and free()s, and I could
         * see the malloc() pool really getting fragmented.  Maybe it
         * wouldn't be an issue in practice; perhaps this will get
         * revisited someday.
         *
         * So, some notes for what's going on:
         *
         * nxtbuf is an array of pointers that contains malloc()'d buffers
         * to hold our component text.  used_buf is an array of struct comp
         * pointers that holds pointers to component structures we found while
         * processing a message.
         *
         * We read in the message with m_getfld(), using "tmpbuf" as our
         * input buffer.  tmpbuf is set at the start of message processing
         * to the first buffer in our buffer pool (nxtbuf).
         *
         * Every time we find a component we care about, we set that component's
         * text buffer to the current value of tmpbuf, and then switch tmpbuf
         * to the next buffer in our pool.  We also add that component to
         * our used_buf pool.
         *
         * When we're done, we go back and zero out all of the component
         * text buffer pointers that we saved in used_buf.
         *
         * Note that this means c_text memory is NOT owned by the fmt_module
         * and it's our responsibility to free it.
         */

        nxtbuf = compbuffers = mh_xcalloc(ncomps, sizeof *nxtbuf);
        used_buf = mh_xcalloc(ncomps + 1, sizeof *used_buf);
        used_buf += ncomps+1; *--used_buf = 0;
        rlwidth = bodycomp && (width > SBUFSIZ)
            ? min (width, NMH_BUFSIZ)
            : SBUFSIZ;
        for (i = ncomps; i--; )
            *nxtbuf++ = mh_xmalloc(rlwidth);
    }

    /*
     * each-message initialization
     */
    nxtbuf = compbuffers;
    savecomp = used_buf;
    tmpbuf = *nxtbuf++;
    startbody = NULL;
    dat[0] = innum ? innum : outnum;
    dat[1] = curflg;
    dat[4] = unseen;

    /*
     * Get the first field.  If the message is non-empty
     * and we're doing an "inc", open the output file.
     */
    bufsz = rlwidth;
    m_getfld_state_reset (&gstate);
    if ((state = m_getfld (&gstate, name, tmpbuf, &bufsz, inb)) == FILEEOF) {
        if (ferror(inb)) {
            advise("read", "unable to"); /* "read error" */
            return SCNFAT;
        }
        return SCNEOF;
    }

    if (outnum) {
        if (outnum > 0) {
            scnmsg = m_name (outnum);
            if (*scnmsg == '?')         /* msg num out of range */
                return SCNNUM;
        } else {
            scnmsg = "/dev/null";
        }
        if ((scnout = fopen (scnmsg, "w")) == NULL)
            adios (scnmsg, "unable to write");
    }

    /* scan - main loop */
    for (compnum = 1; ;
        bufsz = rlwidth, state = m_getfld (&gstate, name, tmpbuf, &bufsz, inb)) {
        switch (state) {
            case FLD: 
            case FLDPLUS: 
                compnum++;
                if (outnum) {
                    FPUTS (name);
                    if ( putc (':', scnout) == EOF) DIEWRERR();
                    FPUTS (tmpbuf);
                }
                /*
                 * if we're interested in this component, save a pointer
                 * to the component text, then start using our next free
                 * buffer as the component temp buffer (buffer switching
                 * saves an extra copy of the component text).
                 */
                if ((cptr = fmt_findcasecomp(name))) {
                    if (! cptr->c_text) {
                        cptr->c_text = tmpbuf;
                        for (cp = tmpbuf + strlen (tmpbuf) - 1; 
                                        cp >= tmpbuf; cp--)
                            if (isspace ((unsigned char) *cp))
                                *cp = 0;
                            else
                                break;
                        *--savecomp = cptr;
                        tmpbuf = *nxtbuf++;
                    }
                }

                while (state == FLDPLUS) {
                    bufsz = rlwidth;
                    state = m_getfld (&gstate, name, tmpbuf, &bufsz, inb);
                    if (outnum)
                        FPUTS (tmpbuf);
                }
                break;

            case BODY: 
                /*
                 * A slight hack ... if we have less than rlwidth characters
                 * in the buffer, call m_getfld again.
                 */

                if ((i = strlen(tmpbuf)) < rlwidth) {
                    bufsz = rlwidth - i;
                    state = m_getfld (&gstate, name, tmpbuf + i, &bufsz, inb);
                }

                if (! outnum) {
                    state = FILEEOF; /* stop now if scan cmd */
                    if (bodycomp && startbody == NULL)
                        startbody = tmpbuf;
                    goto finished;
                }
                if (putc ('\n', scnout) == EOF) DIEWRERR();
                FPUTS (tmpbuf);
                /*
                 * The previous code here used to call m_getfld() using
                 * pointers to the underlying output stdio buffers to
                 * avoid the extra copy.  Tests by Markus Schnalke show
                 * no noticeable performance loss on larger mailboxes
                 * if we incur an extra copy, and messing around with
                 * internal stdio buffers is becoming more and more
                 * unportable as times go on.  So from now on just deal
                 * with the overhead of an extra copy.
                 *
                 * Subtle change - with the previous code tmpbuf wasn't
                 * used, so we could reuse it for the {body} component.
                 * Now since we're using tmpbuf as our read buffer we
                 * need to save the beginning of the body for later.
                 * See the above (and below) use of startbody.
                 */
body:;
                if (bodycomp && startbody == NULL) {
                    startbody = tmpbuf;
                    tmpbuf = *nxtbuf++;
                }

                while (state == BODY) {
                    bufsz = rlwidth;
                    state = m_getfld (&gstate, name, tmpbuf, &bufsz, inb);
                    FPUTS(tmpbuf);
                }
                goto finished;

            case LENERR: 
            case FMTERR: 
                if (innum)
                    fprintf (stderr, "??Format error (message %d) in ",
                             outnum ? outnum : innum);
                else
                    fprintf (stderr, "??Format error in ");

                fprintf (stderr, "component %d\n", compnum);

                if (outnum) {
                    FPUTS ("\n\nBAD MSG:\n");
                    FPUTS (name);
                    if (putc ('\n', scnout) == EOF) DIEWRERR();
                    state = BODY;
                    goto body;
                }
                /* FALLTHRU */

            case FILEEOF:
                goto finished;

            default: 
                adios (NULL, "getfld() returned %d", state);
        }
    }

    /*
     * format and output the scan line.
     */
finished:
    if (ferror(inb)) {
        advise("read", "unable to"); /* "read error" */
        return SCNFAT;
    }

    /* Save and restore buffer so we don't trash our dynamic pool! */
    if (bodycomp) {
        saved_c_text = bodycomp->c_text;
        bodycomp->c_text = startbody;
    }

    if (size)
        dat[2] = size;
    else if (outnum > 0)
    {
        dat[2] = ftell(scnout);
        if (dat[2] == EOF) DIEWRERR();
    }

    if ((datecomp && !datecomp->c_text) || (!size && !outnum)) {
        struct stat st;

        fstat (fileno(inb), &st);
        if (!size && !outnum)
            dat[2] = st.st_size;
        if (datecomp) {
            if (! datecomp->c_text) {
                if (datecomp->c_tws == NULL)
                    NEW0(datecomp->c_tws);
                *datecomp->c_tws = *dlocaltime ((time_t *) &st.st_mtime);
                datecomp->c_flags |= CF_DATEFAB|CF_TRUE;
            } else {
                datecomp->c_flags &= ~CF_DATEFAB;
            }
        }
    }

    fmt_scan (fmt, *scanl, slwidth, dat, NULL);

    if (bodycomp)
        bodycomp->c_text = saved_c_text;

    if (noisy)
        fputs (charstring_buffer (*scanl), stdout);

    cptr = fmt_findcomp ("encrypted");
    encrypted = cptr && cptr->c_text;

    /* return dynamically allocated buffers to pool */
    while ((cptr = *savecomp++)) {
        cptr->c_text = NULL;
    }

    if (outnum && (ferror(scnout) || fclose (scnout) == EOF))
        DIEWRERR();

    return (state != FILEEOF ? SCNERR : encrypted ? SCNENC : SCNMSG);
}


/* The following two functions allow access to the global gstate above. */
void
scan_finished () {
    m_getfld_state_destroy (&gstate);
}

void
scan_detect_mbox_style (FILE *f) {
    m_unknown (&gstate, f);
}