/* Implementation for file attribute munging features.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "cvs.h"
#include "getline.h"
#include "fileattr.h"
#include <assert.h>

static void fileattr_read PROTO ((void));
static int writeattr_proc PROTO ((Node *, void *));

/* Where to look for CVSREP_FILEATTR.  */
static char *fileattr_stored_repos;

/* The in-memory attributes.  */
static List *attrlist;
static char *fileattr_default_attrs;
/* We have already tried to read attributes and failed in this directory
   (for example, there is no CVSREP_FILEATTR file).  */
static int attr_read_attempted;

/* Have the in-memory attributes been modified since we read them?  */
static int attrs_modified;

/* Note that if noone calls fileattr_get, this is very cheap.  No stat(),
   no open(), no nothing.  */
void
fileattr_startdir (repos)
    char *repos;
{
    assert (fileattr_stored_repos == NULL);
    fileattr_stored_repos = xstrdup (repos);
    assert (attrlist == NULL);
    attr_read_attempted = 0;
}

static void
fileattr_delproc (node)
    Node *node;
{
    assert (node->data != NULL);
    free (node->data);
    node->data = NULL;
}

/* Read all the attributes for the current directory into memory.  */
static void
fileattr_read ()
{
    char *fname;
    FILE *fp;
    char *line = NULL;
    size_t line_len = 0;

    /* If there are no attributes, don't waste time repeatedly looking
       for the CVSREP_FILEATTR file.  */
    if (attr_read_attempted)
	return;

    /* If NULL was passed to fileattr_startdir, then it isn't kosher to look
       at attributes.  */
    assert (fileattr_stored_repos != NULL);

    fname = xmalloc (strlen (fileattr_stored_repos)
		     + 1
		     + sizeof (CVSREP_FILEATTR)
		     + 1);

    strcpy (fname, fileattr_stored_repos);
    strcat (fname, "/");
    strcat (fname, CVSREP_FILEATTR);

    attr_read_attempted = 1;
    fp = fopen (fname, FOPEN_BINARY_READ);
    if (fp == NULL)
    {
	if (!existence_error (errno))
	    error (0, errno, "cannot read %s", fname);
	free (fname);
	return;
    }
    attrlist = getlist ();
    while (1) {
	int nread;
	nread = getline (&line, &line_len, fp);
	if (nread < 0)
	    break;
	/* Remove trailing newline.  */
	line[nread - 1] = '\0';
	if (line[0] == 'F')
	{
	    char *p;
	    Node *newnode;

	    p = strchr (line, '\t');
	    *p++ = '\0';
	    newnode = getnode ();
	    newnode->type = FILEATTR;
	    newnode->delproc = fileattr_delproc;
	    newnode->key = xstrdup (line + 1);
	    newnode->data = xstrdup (p);
	    addnode (attrlist, newnode);
	}
	else if (line[0] == 'D')
	{
	    char *p;
	    /* Currently nothing to skip here, but for future expansion,
	       ignore anything located here.  */
	    p = strchr (line, '\t');
	    ++p;
	    fileattr_default_attrs = xstrdup (p);
	}
	/* else just ignore the line, for future expansion.  */
    }
    if (ferror (fp))
	error (0, errno, "cannot read %s", fname);
    if (line != NULL)
	free (line);
    if (fclose (fp) < 0)
	error (0, errno, "cannot close %s", fname);
    attrs_modified = 0;
    free (fname);
}

char *
fileattr_get (filename, attrname)
    char *filename;
    char *attrname;
{
    Node *node;
    size_t attrname_len = strlen (attrname);
    char *p;

    if (attrlist == NULL)
	fileattr_read ();
    if (attrlist == NULL)
	/* Either nothing has any attributes, or fileattr_read already printed
	   an error message.  */
	return NULL;

    if (filename == NULL)
	p = fileattr_default_attrs;
    else
    {
	node = findnode (attrlist, filename);
	if (node == NULL)
	    /* A file not mentioned has no attributes.  */
	    return NULL;
	p = node->data;
    }
    while (p)
    {
	if (strncmp (attrname, p, attrname_len) == 0
	    && p[attrname_len] == '=')
	{
	    /* Found it.  */
	    return p + attrname_len + 1;
	}
	p = strchr (p, ';');
	if (p == NULL)
	    break;
	++p;
    }
    /* The file doesn't have this attribute.  */
    return NULL;
}

char *
fileattr_get0 (filename, attrname)
    char *filename;
    char *attrname;
{
    char *cp;
    char *cpend;
    char *retval;

    cp = fileattr_get (filename, attrname);
    if (cp == NULL)
	return NULL;
    cpend = strchr (cp, ';');
    if (cpend == NULL)
	cpend = cp + strlen (cp);
    retval = xmalloc (cpend - cp + 1);
    strncpy (retval, cp, cpend - cp);
    retval[cpend - cp] = '\0';
    return retval;
}

char *
fileattr_modify (list, attrname, attrval, namevalsep, entsep)
    char *list;
    char *attrname;
    char *attrval;
    int namevalsep;
    int entsep;
{
    char *retval;
    char *rp;
    size_t attrname_len = strlen (attrname);

    /* Portion of list before the attribute to be replaced.  */
    char *pre;
    char *preend;
    /* Portion of list after the attribute to be replaced.  */
    char *post;

    char *p;
    char *p2;

    p = list;
    pre = list;
    preend = NULL;
    /* post is NULL unless set otherwise.  */
    post = NULL;
    p2 = NULL;
    if (list != NULL)
    {
	while (1) {
	    p2 = strchr (p, entsep);
	    if (p2 == NULL)
	    {
		p2 = p + strlen (p);
		if (preend == NULL)
		    preend = p2;
	    }
	    else
		++p2;
	    if (strncmp (attrname, p, attrname_len) == 0
		&& p[attrname_len] == namevalsep)
	    {
		/* Found it.  */
		preend = p;
		if (preend > list)
		    /* Don't include the preceding entsep.  */
		    --preend;

		post = p2;
	    }
	    if (p2[0] == '\0')
		break;
	    p = p2;
	}
    }
    if (post == NULL)
	post = p2;

    if (preend == pre && attrval == NULL && post == p2)
	return NULL;

    retval = xmalloc ((preend - pre)
		      + 1
		      + (attrval == NULL ? 0 : (attrname_len + 1
						+ strlen (attrval)))
		      + 1
		      + (p2 - post)
		      + 1);
    if (preend != pre)
    {
	strncpy (retval, pre, preend - pre);
	rp = retval + (preend - pre);
	if (attrval != NULL)
	    *rp++ = entsep;
	*rp = '\0';
    }
    else
	retval[0] = '\0';
    if (attrval != NULL)
    {
	strcat (retval, attrname);
	rp = retval + strlen (retval);
	*rp++ = namevalsep;
	strcpy (rp, attrval);
    }
    if (post != p2)
    {
	rp = retval + strlen (retval);
	if (preend != pre || attrval != NULL)
	    *rp++ = entsep;
	strncpy (rp, post, p2 - post);
	rp += p2 - post;
	*rp = '\0';
    }
    return retval;
}

void
fileattr_set (filename, attrname, attrval)
    char *filename;
    char *attrname;
    char *attrval;
{
    Node *node;
    char *p;

    attrs_modified = 1;

    if (filename == NULL)
    {
	p = fileattr_modify (fileattr_default_attrs, attrname, attrval,
			     '=', ';');
	if (fileattr_default_attrs != NULL)
	    free (fileattr_default_attrs);
	fileattr_default_attrs = p;
	return;
    }
    if (attrlist == NULL)
	fileattr_read ();
    if (attrlist == NULL)
    {
	/* Not sure this is a graceful way to handle things
	   in the case where fileattr_read was unable to read the file.  */
        /* No attributes existed previously.  */
	attrlist = getlist ();
    }

    node = findnode (attrlist, filename);
    if (node == NULL)
    {
	if (attrval == NULL)
	    /* Attempt to remove an attribute which wasn't there.  */
	    return;

	/* First attribute for this file.  */
	node = getnode ();
	node->type = FILEATTR;
	node->delproc = fileattr_delproc;
	node->key = xstrdup (filename);
	node->data = xmalloc (strlen (attrname) + 1 + strlen (attrval) + 1);
	strcpy (node->data, attrname);
	strcat (node->data, "=");
	strcat (node->data, attrval);
	addnode (attrlist, node);
    }

    p = fileattr_modify (node->data, attrname, attrval, '=', ';');
    free (node->data);
    node->data = NULL;
    if (p == NULL)
	delnode (node);
    else
	node->data = p;
}

void
fileattr_newfile (filename)
    char *filename;
{
    Node *node;

    if (attrlist == NULL)
	fileattr_read ();

    if (fileattr_default_attrs == NULL)
	return;

    if (attrlist == NULL)
    {
	/* Not sure this is a graceful way to handle things
	   in the case where fileattr_read was unable to read the file.  */
        /* No attributes existed previously.  */
	attrlist = getlist ();
    }

    node = getnode ();
    node->type = FILEATTR;
    node->delproc = fileattr_delproc;
    node->key = xstrdup (filename);
    node->data = xstrdup (fileattr_default_attrs);
    addnode (attrlist, node);
    attrs_modified = 1;
}

static int
writeattr_proc (node, data)
    Node *node;
    void *data;
{
    FILE *fp = (FILE *)data;
    fputs ("F", fp);
    fputs (node->key, fp);
    fputs ("\t", fp);
    fputs (node->data, fp);
    fputs ("\012", fp);
    return 0;
}

void
fileattr_write ()
{
    FILE *fp;
    char *fname;
    mode_t omask;

    if (!attrs_modified)
	return;

    if (noexec)
	return;

    /* If NULL was passed to fileattr_startdir, then it isn't kosher to set
       attributes.  */
    assert (fileattr_stored_repos != NULL);

    fname = xmalloc (strlen (fileattr_stored_repos)
		     + 1
		     + sizeof (CVSREP_FILEATTR)
		     + 1);

    strcpy (fname, fileattr_stored_repos);
    strcat (fname, "/");
    strcat (fname, CVSREP_FILEATTR);

    if (list_isempty (attrlist) && fileattr_default_attrs == NULL)
    {
	/* There are no attributes.  */
	if (unlink_file (fname) < 0)
	{
	    if (!existence_error (errno))
	    {
		error (0, errno, "cannot remove %s", fname);
	    }
	}

	/* Now remove CVSREP directory, if empty.  The main reason we bother
	   is that CVS 1.6 and earlier will choke if a CVSREP directory
	   exists, so provide the user a graceful way to remove it.  */
	strcpy (fname, fileattr_stored_repos);
	strcat (fname, "/");
	strcat (fname, CVSREP);
	if (rmdir (fname) < 0)
	{
	    if (errno != ENOTEMPTY

		/* Don't know why we would be here if there is no CVSREP
		   directory, but it seemed to be happening anyway, so
		   check for it.  */
		&& !existence_error (errno))
		error (0, errno, "cannot remove %s", fname);
	}

	free (fname);
	return;
    }

    omask = umask (cvsumask);
    fp = fopen (fname, FOPEN_BINARY_WRITE);
    if (fp == NULL)
    {
	if (existence_error (errno))
	{
	    /* Maybe the CVSREP directory doesn't exist.  Try creating it.  */
	    char *repname;

	    repname = xmalloc (strlen (fileattr_stored_repos)
			       + 1
			       + sizeof (CVSREP)
			       + 1);
	    strcpy (repname, fileattr_stored_repos);
	    strcat (repname, "/");
	    strcat (repname, CVSREP);

	    if (CVS_MKDIR (repname, 0777) < 0 && errno != EEXIST)
	    {
		error (0, errno, "cannot make directory %s", repname);
		(void) umask (omask);
		free (repname);
		return;
	    }
	    free (repname);

	    fp = fopen (fname, FOPEN_BINARY_WRITE);
	}
	if (fp == NULL)
	{
	    error (0, errno, "cannot write %s", fname);
	    (void) umask (omask);
	    return;
	}
    }
    (void) umask (omask);
    walklist (attrlist, writeattr_proc, fp);
    if (fileattr_default_attrs != NULL)
    {
	fputs ("D\t", fp);
	fputs (fileattr_default_attrs, fp);
	fputs ("\012", fp);
    }
    if (fclose (fp) < 0)
	error (0, errno, "cannot close %s", fname);
    attrs_modified = 0;
    free (fname);
}

void
fileattr_free ()
{
    dellist (&attrlist);
    if (fileattr_stored_repos != NULL)
	free (fileattr_stored_repos);
    fileattr_stored_repos = NULL;
    if (fileattr_default_attrs != NULL)
	free (fileattr_default_attrs);
    fileattr_default_attrs = NULL;
}