/* Copyright (c) 2002-2018 Pigeonhole authors, see the included COPYING file

 */

/* Match-type ':regex'

 */

#include "lib.h"

#include "mempool.h"

#include "buffer.h"

#include "array.h"

#include "str.h"

#include "str-sanitize.h"

#include "sieve-common.h"

#include "sieve-limits.h"

#include "sieve-ast.h"

#include "sieve-stringlist.h"

#include "sieve-commands.h"

#include "sieve-validator.h"

#include "sieve-interpreter.h"

#include "sieve-comparators.h"

#include "sieve-match-types.h"

#include "sieve-match.h"

#include "ext-regex-common.h"

#include "dregex.h"

#include <sys/types.h>

#include <ctype.h>

/*

 * Configuration

 */

#define MCHT_REGEX_MAX_SUBSTITUTIONS SIEVE_MAX_MATCH_VALUES

/*

 * Match type

 */

static bool

mcht_regex_validate_context(struct sieve_validator *valdtr,

          struct sieve_ast_argument *arg,

          struct sieve_match_type_context *ctx,

          struct sieve_ast_argument *key_arg);

static void mcht_regex_match_init(struct sieve_match_context *mctx);

static int

mcht_regex_match_keys(struct sieve_match_context *mctx,

          const char *val, size_t val_size,

          struct sieve_stringlist *key_list);

static void mcht_regex_match_deinit(struct sieve_match_context *mctx);

const struct sieve_match_type_def regex_match_type = {

  SIEVE_OBJECT("regex", &regex_match_type_operand, 0),

  .validate_context = mcht_regex_validate_context,

  .match_init = mcht_regex_match_init,

  .match_keys = mcht_regex_match_keys,

  .match_deinit = mcht_regex_match_deinit,

};

/*

 * Match type validation

 */

static int

mcht_regex_validate_regexp(struct sieve_validator *valdtr,

         struct sieve_match_type_context *mtctx ATTR_UNUSED,

         struct sieve_ast_argument *key, int cflags)

{

  int ret;

  const char *dregex_str = sieve_ast_argument_strc(key);

  const char *error;

  struct dregex_code *code = dregex_code_create();

  ret = dregex_code_compile(code, dregex_str, cflags, &error);

  dregex_code_free(&code);

  if (ret != 0) {

    sieve_argument_validate_error(

      valdtr, key,

      "invalid regular expression '%s' for regex match: %s",

      str_sanitize(dregex_str, 128),

      error);

    return -1;

  }

  return 1;

}

struct _regex_key_context {

  struct sieve_validator *valdtr;

  struct sieve_match_type_context *mtctx;

  int cflags;

};

static int

mcht_regex_validate_key_argument(void *context, struct sieve_ast_argument *key)

{

  struct _regex_key_context *keyctx = (struct _regex_key_context *)context;

  /* FIXME: We can currently only handle string literal argument, so

     variables are not allowed.

   */

  if (sieve_argument_is_string_literal(key)) {

    return mcht_regex_validate_regexp(keyctx->valdtr, keyctx->mtctx,

              key, keyctx->cflags);

  }

  return 1;

}

static bool

mcht_regex_validate_context(struct sieve_validator *valdtr,

          struct sieve_ast_argument *arg ATTR_UNUSED,

          struct sieve_match_type_context *mtctx,

          struct sieve_ast_argument *key_arg)

{

  const struct sieve_comparator *cmp = mtctx->comparator;

  int cflags = DREGEX_NOSUB;

  struct _regex_key_context keyctx;

  struct sieve_ast_argument *kitem;

  if (cmp != NULL) {

    if (sieve_comparator_is(cmp, i_ascii_casemap_comparator))

      cflags |= DREGEX_ICASE | DREGEX_ASCII_ONLY;

    else if (sieve_comparator_is(cmp, i_octet_comparator))

      cflags |= DREGEX_ASCII_ONLY;

    else if (sieve_comparator_is(cmp, i_unicode_casemap_comparator))

      cflags |= DREGEX_ICASE;

    else {

      sieve_argument_validate_error(

        valdtr, mtctx->argument,

        "regex match type only supports "

        "i;octet, i;ascii-casemap and i;unicode-casemap comparators");

      return FALSE;

    }

  }

  /* Validate regular expression keys */

  keyctx.valdtr = valdtr;

  keyctx.mtctx = mtctx;

  keyctx.cflags = cflags;

  kitem = key_arg;

  if (sieve_ast_stringlist_map(&kitem, &keyctx,

             mcht_regex_validate_key_argument) <= 0)

    return FALSE;

  return TRUE;

}

/*

 * Match type implementation

 */

struct mcht_regex_key {

  struct dregex_code *regexp;

  int status;

};

struct mcht_regex_context {

  ARRAY(struct mcht_regex_key) reg_expressions;

  ARRAY_TYPE(const_string) pmatch;

  bool all_compiled:1;

  bool capture_groups;

};

static void mcht_regex_match_init(struct sieve_match_context *mctx)

{

  pool_t pool = mctx->pool;

  struct mcht_regex_context *ctx;

  /* Create context */

  ctx = p_new(pool, struct mcht_regex_context, 1);

  /* Create storage for match values if match values are requested */

  ctx->capture_groups = sieve_match_values_are_enabled(mctx->runenv);

  /* Assign context */

  mctx->data = ctx;

}

static int

mcht_regex_match_key(struct sieve_match_context *mctx, const char *val,

         struct dregex_code *code)

{

  struct mcht_regex_context *ctx =

    (struct mcht_regex_context *)mctx->data;

  const char *error;

  int ret;

  ARRAY_TYPE(const_string) pmatch;

  if (ctx->capture_groups)

    t_array_init(&pmatch, 8);

  /* Execute regex */

  if (!ctx->capture_groups)

    ret = dregex_code_match(code, val, &error);

  else

    ret = dregex_code_match_groups(code, val, &pmatch, &error);

  /* Handle match values if necessary */

  if (ret > 0) {

    if (ctx->capture_groups && array_count(&pmatch) > 0) {

      struct sieve_match_values *mvalues;

      string_t *subst = t_str_new(32);

      const char *mvalue;

      /* Start new list of match values */

      mvalues = sieve_match_values_start(mctx->runenv);

      i_assert(mvalues != NULL);

      array_foreach_elem(&pmatch, mvalue) {

        str_append(subst, mvalue);

        sieve_match_values_add(mvalues, subst);

        str_truncate(subst, 0);

      }

      /* Substitute the new match values */

      sieve_match_values_commit(mctx->runenv, &mvalues);

    }

    return 1;

  }

  return 0;

}

static int

mcht_regex_match_keys(struct sieve_match_context *mctx,

          const char *val, size_t val_size ATTR_UNUSED,

          struct sieve_stringlist *key_list)

{

  const struct sieve_runtime_env *renv = mctx->runenv;

  bool trace = sieve_runtime_trace_active(renv, SIEVE_TRLVL_MATCHING);

  struct mcht_regex_context *ctx =

    (struct mcht_regex_context *)mctx->data;

  const struct sieve_comparator *cmp = mctx->comparator;

  int match;

  if (!ctx->all_compiled) {

    string_t *key_item = NULL;

    unsigned int i;

    int ret;

    /* Regular expressions still need to be compiled */

    if (!array_is_created(&ctx->reg_expressions))

      p_array_init(&ctx->reg_expressions, mctx->pool, 16);

    i = 0;

    match = 0;

    while (match == 0 &&

           (ret = sieve_stringlist_next_item(key_list, &key_item)) > 0) {

      T_BEGIN {

        struct mcht_regex_key *rkey;

        if (i >= array_count(&ctx->reg_expressions)) {

          int cflags = 0;

          rkey = array_append_space(&ctx->reg_expressions);

          /* Configure case-sensitivity according to comparator */

          if (sieve_comparator_is(cmp, i_octet_comparator))

            cflags |= DREGEX_ASCII_ONLY;

          else if (sieve_comparator_is(cmp, i_ascii_casemap_comparator))

            cflags |= (DREGEX_ICASE | DREGEX_ASCII_ONLY);

          else if (sieve_comparator_is(cmp, i_unicode_casemap_comparator))

            cflags |= DREGEX_ICASE;

          else

            rkey->status = -1; /* Not supported */

          if (rkey->status >= 0) {

            const char *dregex_str = str_c(key_item);

            const char *error;

            int rxret;

            /* Indicate whether match values need to be produced */

            if (!ctx->capture_groups)

              cflags |= DREGEX_NOSUB;

            struct dregex_code *code = dregex_code_create();

            /* Compile regular expression */

            rxret = dregex_code_compile(code, dregex_str, cflags, &error);

            if (rxret != 0) {

              sieve_runtime_error(renv, NULL,

                "invalid regular expression '%s' for regex match: %s",

                str_sanitize(dregex_str, 128),

                error);

              rkey->status = -1;

              dregex_code_free(&code);

            } else {

              rkey->status = 1;

              rkey->regexp = code;

            }

          }

        } else {

          rkey = array_idx_modifiable(&ctx->reg_expressions, i);

        }

        if (rkey->status > 0) {

          match = mcht_regex_match_key(

            mctx, val, rkey->regexp);

          if (trace) {

            sieve_runtime_trace(renv, 0,

              "with regex '%s' [id=%u] => %d",

              str_sanitize(str_c(key_item), 80),

              i, match);

          }

        }

      } T_END;

      i++;

    }

    if (ret == 0) {

      ctx->all_compiled = TRUE;

    } else if (ret < 0) {

      mctx->exec_status = key_list->exec_status;

      match = -1;

    }

  } else {

    const struct mcht_regex_key *rkeys;

    unsigned int i, count;

    /* Regular expressions are compiled */

    rkeys = array_get(&ctx->reg_expressions, &count);

    i = 0;

    match = 0;

    while (match == 0 && i < count) {

      if (rkeys[i].status > 0) {

        match = mcht_regex_match_key(

          mctx, val, rkeys[i].regexp);

        if (trace) {

          sieve_runtime_trace(renv, 0,

            "with compiled regex [id=%u] => %d",

            i, match);

        }

      }

      i++;

    }

  }

  return match;

}

void mcht_regex_match_deinit(struct sieve_match_context *mctx)

{

  struct mcht_regex_context *ctx =

    (struct mcht_regex_context *)mctx->data;

  struct mcht_regex_key *rkeys;

  unsigned int count, i;

  /* Clean up compiled regular expressions */

  if (array_is_created(&ctx->reg_expressions)) {

    rkeys = array_get_modifiable(&ctx->reg_expressions, &count);

    for (i = 0; i < count; i++)

      dregex_code_free(&rkeys[i].regexp);

  }

}