[visor] / libvisor / src / visor.c

/*
visor - lightweight system-independent embeddable text editor framework
Copyright (C)  2019 John Tsiombikas <nuclear@member.fsf.org>

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License
along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

#include "vilibc.h"
#include "visor.h"
#include "vimpl.h"

#define vi_malloc       vi->mm.malloc
#define vi_free         vi->mm.free
#define vi_realloc      vi->mm.realloc

#define vi_open         vi->fop.open
#define vi_size         vi->fop.size
#define vi_close        vi->fop.close
#define vi_map          vi->fop.map
#define vi_unmap        vi->fop.unmap
#define vi_read         vi->fop.read
#define vi_write        vi->fop.write
#define vi_seek         vi->fop.seek

#ifdef HAVE_LIBC
static const struct vi_alloc stdalloc = { malloc, free, realloc };
#endif

struct visor *vi_create(struct vi_alloc *mm)
{
        struct visor *vi;

#ifdef HAVE_LIBC
        if(!mm) mm = &stdalloc;
#else
        if(!mm) return 0;
#endif

        if(!(vi = mm->malloc(sizeof *vi))) {
                return 0;
        }
        memset(vi, 0, sizeof *vi);
        vi->mm = *mm;

        return vi;
}

void vi_destroy(struct visor *vi)
{
        while(vi->buflist) {
                vi_delete_buf(vi, vi->buflist);
        }
        vi_free(vi);
}

void vi_set_fileops(struct visor *vi, struct vi_fileops *fop)
{
        vi->fop = *fop;
}

void vi_set_ttyops(struct visor *vi, struct vi_ttyops *tty)
{
        vi->tty = *tty;
}

struct vi_buffer *vi_new_buf(struct visor *vi, const char *path)
{
        struct vi_buffer *nb;

        if(!(nb = vi_malloc(sizeof *nb))) {
                vi_error(vi, "failed to allocate new buffer\n");
                return 0;
        }
        memset(nb, 0, sizeof *nb);
        nb->vi = vi;

        if(path) {
                if(vi_buf_read(nb, path) == -1) {
                        vi_free(nb);
                        return 0;
                }
        }

        if(vi->buflist) {
                struct vi_buffer *last = vi->buflist->prev;
                nb->prev = last;
                nb->next = vi->buflist;
                last->next = nb;
                vi->buflist->prev = nb;
        } else {
                nb->next = nb->prev = nb;
                vi->buflist = nb;
        }
        return nb;
}

static int remove_buf(struct visor *vi, struct vi_buffer *vb)
{
        if(!vi->buflist) {
                vi_error(vi, "failed to remove a buffer which doesn't exist\n");
                return -1;
        }

        if(vb->next == vb) {
                if(vi->buflist != vb) {
                        vi_error(vi, "failed to remove buffer, buffer list inconsistency\n");
                        return -1;
                }
                vi->buflist = 0;
                return 0;
        }

        if(vi->buflist == vb) {
                vi->buflist = vb->next;
        }
        vb->prev->next = vb->next;
        vb->next->prev = vb->prev;
        vb->next = vb->prev = vb;
        return 0;
}

int vi_delete_buf(struct visor *vi, struct vi_buffer *vb)
{
        if(remove_buf(vi, vb) == -1) {
                return -1;
        }

        vi_free(vb->path);
        vi_free(vb->orig);
        vi_free(vb->add);
        vi_free(vb->spans);
        return 0;
}

int vi_num_buf(struct visor *vi)
{
        int count;
        struct vi_buffer *vb;

        if(!vi->buflist) return 0;

        count = 1;
        vb = vi->buflist->next;
        while(vb != vi->buflist) {
                count++;
                vb = vb->next;
        }
        return count;
}

struct vi_buffer *vi_getcur_buf(struct visor *vi)
{
        return vi->buflist;
}

void vi_setcur_buf(struct visor *vi, struct vi_buffer *vb)
{
        vi->buflist = vb;
}

struct vi_buffer *vi_next_buf(struct visor *vi)
{
        return vi->buflist ? vi->buflist->next : 0;
}

struct vi_buffer *vi_prev_buf(struct visor *vi)
{
        return vi->buflist ? vi->buflist->prev : 0;
}

/* split_span splits the span sp. if size > 0 it moves the second part to sp+2,
 * leaving an empty place at sp+1 for the new span. The start point of the
 * second part is adjusted by size.
 *
 * It can't fail, because it's always called with the span array having at
 * least two empty slots (see: add_span).
 */
void split_span(struct vi_buffer *vb, struct vi_span *sp, vi_addr at, unsigned long size)
{
        struct vi_span *tail = sp + (size ? 2 : 1);
        int num_move = vb->num_spans - sp - 1;

        memmove(tail + 1, sp + 1, num_move);
        vb->num_span += tail - sp;

        sp->size ... CONTINUE HERE.
}

static int add_span(struct vi_buffer *vb, vi_addr at, int src, vi_addr start, unsigned long size)
{
        int i;
        struct visor *vi = vb->vi;
        struct vi_span *sp;

        /* make sure we have space for at least two new spans (split + add) */
        if(vb->num_spans + 1 >= vb->max_spans) {
                int newmax = vb->max_spans > 0 ? (vb->max_spans << 1) : 16;
                struct vi_span *tmp = vi_realloc(vb->spans, newmax * sizeof *tmp);
                if(!tmp) return -1;
                vb->spans = tmp;
                vb->max_spans = newmax;
        }

        if((sp = vi_buf_find_span(vb, at))) {
                split_span(vb, sp++, at, size);
        } else {
                sp = vb->spans + vb->num_spans;
        }

        sp->src = src;
        sp->addr = start;
        sp->size = size;
        vb->num_spans++;
        return 0;
}

void vi_buf_reset(struct vi_buffer *vb)
{
        struct visor *vi = vb->vi;
        struct vi_buffer *prev, *next;

        vi_free(vb->path);

        if(vb->fp) {
                if(vb->file_mapped) vi_unmap(vb->fp);
                vi_close(vb->fp);
        }
        vi_free(vb->orig);
        vi_free(vb->add);
        vi_free(vb->spans);

        prev = vb->prev;
        next = vb->next;
        memset(vb, 0, sizeof *vb);
        vb->prev = prev;
        vb->next = next;
}

int vi_buf_read(struct vi_buffer *vb, const char *path)
{
        struct visor *vi = vb->vi;
        vi_file *fp;
        unsigned long fsz;
        int plen;

        vi_buf_reset(vb);

        if(!(fp = vi_open(path))) {
                return -1;
        }
        plen = strlen(path);
        if(!(vb->path = vi_malloc(plen + 1))) {
                vi_error(vi, "failed to allocate path name buffer\n");
                vi_buf_reset(vb);
                return -1;
        }
        memcpy(vb->path, path, plen + 1);

        vb->num_spans = 0;

        if((fsz = vi_size(fp))) {
                /* existing file, map it into memory, or failing that read it */
                if(!vi->fop.map || !(vb->orig = vi_map(fp))) {
                        if(!(vb->orig = vi_malloc(fsz))) {
                                vi_buf_reset(vb);
                                return -1;
                        }
                } else {
                        vb->file_mapped = 1;
                }

                if(add_span(vb, SPAN_ORIG, 0, fsz) == -1) {
                        vi_error(vi, "failed to allocate span\n");
                        vi_buf_reset(vb);
                        return -1;
                }
        }
        vb->orig_size = fsz;
        return 0;
}

int vi_buf_write(struct vi_buffer *vb, const char *path)
{
}