/* -*- c-file-style: "java"; indent-tabs-mode: nil; tab-width: 4; fill-column: 78 -*-
 *
 * Copyright 2007 Google Inc.
 *
 * 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
 * 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 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 */

#include <config.h>

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "distcc.h"
#include "exitcode.h"
#include "dotd.h"
#include "snprintf.h"

/* The dotd file is compiler generated,
 * so it should not have lines with more than
 * twice the length of the maximum path length.
 */
#define MAX_DOTD_LINE_LEN (MAXPATHLEN * 2)

/* Replaces the first occurrence of needle in haystack with
   new_needle. haystack must be of at least hay_size,
   and hay_size must be large enough to hold the string
   after the replacement.
   new_needle should not overlap with the haystack.
   Returns 0 if all goes well, 1 otherwise.
*/
static int dcc_strgraft(char *haystack, size_t hay_size,
                        const char *needle, const char *new_needle)
{
    char *found;
    size_t needle_len = 0;
    size_t new_needle_len = 0;

    found = strstr(haystack, needle);
    if (found == NULL)
        return 0;

    needle_len = strlen(needle);
    new_needle_len = strlen(new_needle);

    if (strlen(haystack) - needle_len + new_needle_len + 1 > hay_size)
        return 1;

    /* make some room in the haystack for the new needle */
    memmove(found + new_needle_len,
            found + needle_len,
            strlen(found + needle_len) + 1);
    memcpy(found, new_needle, new_needle_len);

    return 0;
}

/* Given the name of a dotd file, and the name of the directory
 * masquerading as root, write a @p new_dotd file that
 * contains everything in dotd, but with the "root" directory removed.
 * It will also substitute client_out_name for server_out_name,
 * rewriting the dependency target.
 */
int dcc_cleanup_dotd(const char *dotd_fname,
                     char **new_dotd_fname,
                     const char *root_dir,
                     const char *client_out_name,
                     const char *server_out_name)
{
    /* When we do the substitution of server-side output name to
     * client-side output name, we may end up with a line that
     * longer than the longest line we expect from the compiler.
     */
    char buf[2 * MAX_DOTD_LINE_LEN];

    FILE *dotd, *tmp_dotd;
    char *found;
    int ret;

    dotd = fopen(dotd_fname, "r");
    if (dotd == NULL) {
        return 1;
    }
    ret = dcc_make_tmpnam(dcc_find_basename(dotd_fname),
                          ".d", new_dotd_fname);

    if (ret) {
        fclose(dotd);
        return ret;
    }

    tmp_dotd = fopen(*new_dotd_fname, "w");
    if (tmp_dotd == NULL) {
        fclose(dotd);
        return 1;
    }

    while (fgets(buf, MAX_DOTD_LINE_LEN, dotd)) {
        if ((strchr(buf, '\n') == NULL) && !feof(dotd)) {
            /* Line length must have exceeded MAX_DOTD_LINE_LEN: bail out. */
            fclose(dotd);
            fclose(tmp_dotd);
            return 1;
        }

        /* First, the dependency target substitution */
        if (dcc_strgraft(buf, sizeof(buf),
                         server_out_name, client_out_name)) {
            fclose(dotd);
            fclose(tmp_dotd);
            return 1;
        }

        /* Second, the trimming of the "root" directory" */
        found = strstr(buf, root_dir);
        while (found) {
            char *rest_of_buf = found + strlen(root_dir);
            memmove(found, rest_of_buf, strlen(rest_of_buf) + 1);
            found = strstr(found, root_dir);
        }
        if (fprintf(tmp_dotd, "%s", buf) < 0) {
            fclose(dotd);
            fclose(tmp_dotd);
            return 1;
        }
    }
    if (ferror(dotd) || ferror(tmp_dotd)) {
       return 1;
    }
    fclose(dotd);
    if (fclose(tmp_dotd) < 0) {
        return 1;
    }
    return 0;
}

/* Go through arguments (in @p argv), and relevant environment variables, and
 * find out where the dependencies output should go.  Return that location in a
 * newly allocated string in @p dotd_fname.  @p needs_dotd is set to true if the
 * compilation command line and environment imply that a .d file must be
 * produced.  @p sets_dotd_target is set to true if there is a -MQ or -MT
 * option.  This is to be used on the client, so that the client knows where to
 * put the .d file it gets from the server. @p dotd_target is set only if
 * @needs_dotd is true and @sets_dotd_target is false and the target is given in
 * the DEPENDENCIES_OUTPUT environment variable.
 *
 * Note: -M is not handled here, because this option implies -E.
 *
 * TODO(manos): it does not support SUNPRO_DEPENDENCIES.
 */
int dcc_get_dotd_info(char **argv, char **dotd_fname,
                      int *needs_dotd, int *sets_dotd_target,
                      char **dotd_target)
{
    char *deps_output = 0;

    char *input_file;
    char *output_file;
    char **new_args;  /* will throw this away */
    int has_dash_o = 0;
    char *env_var = 0;
    int i;
    char *a;

    *needs_dotd = 0;
    *sets_dotd_target = 0;
    *dotd_target = NULL;

    env_var = getenv("DEPENDENCIES_OUTPUT");

    if (env_var != NULL) {
        *needs_dotd = 1;
    }

    for (i = 0; (a = argv[i]); i++) {
        if (strcmp(a, "-MT") == 0) {
            *sets_dotd_target = 1;
            ++i;
            continue;
        }
        if (strcmp(a, "-MQ") == 0) {
            *sets_dotd_target = 1;
            ++i;
            continue;
        }
        /* Catch-all for all -MD, -MMD, etc, options.
         * -MQ and -MT do not imply a deps file is expected.
         */
        if (strncmp(a, "-M", 2) == 0) {
            *needs_dotd = 1;
        }
        if (strcmp(a, "-MF") == 0) {
            ++i;
            deps_output = argv[i];
        } else if (strncmp(a, "-MF", 3) == 0) {
            deps_output = argv[i] + 3;
        } else if (strcmp(a, "-o") == 0) {
            has_dash_o = 1;
        }
    }

    /* TODO(csilvers): we also need to parse -Wp,-x,-y,-z, in the same
     * way we do gcc flags in the for loop above.  Note that the -Wp
     * flags are passed to cpp, with slightly different semantics than
     * gcc flags (eg -Wp,-MD takes a filename argument, while -MD does
     * not).
     */

    if (deps_output) {
        *dotd_fname = strdup(deps_output);
        if (*dotd_fname == NULL) {
            return EXIT_OUT_OF_MEMORY;
        } else {
            return 0;
        }
    }

    /* ok, so there is no explicit setting of the deps filename. */
    deps_output = env_var;
    if (deps_output) {
        char *space;
        *dotd_fname = strdup(deps_output);
        if (*dotd_fname == NULL) {
            return EXIT_OUT_OF_MEMORY;
        }
        space = strchr(*dotd_fname, ' ');
        if (space != NULL) {
            *space = '\0';
            *dotd_target = space + 1;
        }

        return 0;
    }

    /* and it's not set explicitly in the variable */

    { /* Call dcc_scan_args to find the input/output files in order to calculate
         a name for the .d file.*/

        char *extension;
        char *tmp_dotd_fname;
        dcc_scan_args(argv, &input_file, &output_file, &new_args);
        /* if .o is set, just append .d.
         * otherwise, take the basename of the input, and set the suffix to .d */
        if (has_dash_o)
          tmp_dotd_fname = strdup(output_file);
        else
          tmp_dotd_fname = strdup(input_file);
        if (tmp_dotd_fname == NULL) return EXIT_OUT_OF_MEMORY;
        extension = dcc_find_extension(tmp_dotd_fname);
        /* Whether derived from input or output filename, we peel the extension
           off (if it exists). */
        if (extension) {
          /* dcc_find_extension guarantees that there is space for 'd'. */
          extension[1] = 'd';
          extension[2] = '\0';
          *dotd_fname = tmp_dotd_fname;
        }
        else { /* There is no extension (or name ends with a "."). */
          if (tmp_dotd_fname[strlen(tmp_dotd_fname) - 1] == '.')
            checked_asprintf(dotd_fname, "%s%s", tmp_dotd_fname, "d");
          else
            checked_asprintf(dotd_fname, "%s%s", tmp_dotd_fname, ".d");
          if (*dotd_fname == NULL) {
            return EXIT_OUT_OF_MEMORY;
          }
          free(tmp_dotd_fname);
        }
        return 0;
    }
}