SQLite

  int nVal,
  sqlite3_value **apVal
){
  ShellState *p = (ShellState*)sqlite3_user_data(pCtx);
  utf8_printf(p->out, "%s\n", sqlite3_value_text(apVal[0]));
  sqlite3_result_value(pCtx, apVal[0]);
}

/*
** SQL function:   edit(VALUE)
**                 edit(VALUE,EDITOR)
**
** These steps:
**
**     (1) Write VALUE into a temporary file.
**     (2) Run program EDITOR on that temporary file.
**     (3) Read the temporary file back and return its content as the result.
**     (4) Delete the temporary file
**
** If the EDITOR argument is omitted, use the value in the VISUAL
** environment variable.  If still there is no EDITOR, through an error.
**
** Also throw an error if the EDITOR program returns a non-zero exit code.
*/
static void editFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  const char *zEditor;
  char *zTempFile = 0;
  sqlite3 *db;
  char *zCmd = 0;
  int bBin;
  int rc;
  FILE *f = 0;
  sqlite3_int64 sz;
  sqlite3_int64 x;
  unsigned char *p = 0;

  if( argc==2 ){
    zEditor = (const char*)sqlite3_value_text(argv[1]);
  }else{
    zEditor = getenv("VISUAL");
  }
  if( zEditor==0 ){
    sqlite3_result_error(context, "no editor for edit()", -1);
    return;
  }
  if( sqlite3_value_type(argv[0])==SQLITE_NULL ){
    sqlite3_result_error(context, "NULL input to edit()", -1);
    return;
  }
  db = sqlite3_context_db_handle(context);
  zTempFile = 0;
  sqlite3_file_control(db, 0, SQLITE_FCNTL_TEMPFILENAME, &zTempFile);
  if( zTempFile==0 ){
    sqlite3_uint64 r = 0;
    sqlite3_randomness(sizeof(r), &r);
    zTempFile = sqlite3_mprintf("temp%llx", r);
    if( zTempFile==0 ){
      sqlite3_result_error_nomem(context);
      return;
    }
  }
  bBin = sqlite3_value_type(argv[0])==SQLITE_BLOB;
  f = fopen(zTempFile, bBin ? "wb" : "w");
  if( f==0 ){
    sqlite3_result_error(context, "edit() cannot open temp file", -1);
    goto edit_func_end;
  }
  sz = sqlite3_value_bytes(argv[0]);
  if( bBin ){
    x = fwrite(sqlite3_value_blob(argv[0]), 1, sz, f);
  }else{
    x = fwrite(sqlite3_value_text(argv[0]), 1, sz, f);
  }
  fclose(f);
  f = 0;
  if( x!=sz ){
    sqlite3_result_error(context, "edit() could not write the whole file", -1);
    goto edit_func_end;
  }
  zCmd = sqlite3_mprintf("%s \"%s\"", zEditor, zTempFile);
  if( zCmd==0 ){
    sqlite3_result_error_nomem(context);
    goto edit_func_end;
  }
  rc = system(zCmd);
  sqlite3_free(zCmd);
  if( rc ){
    sqlite3_result_error(context, "EDITOR returned non-zero", -1);
    goto edit_func_end;
  }
  f = fopen(zTempFile, bBin ? "rb" : "r");
  if( f==0 ){
    sqlite3_result_error(context,
      "edit() cannot reopen temp file after edit", -1);
    goto edit_func_end;
  }
  fseek(f, 0, SEEK_END);
  sz = ftell(f);
  rewind(f);
  p = sqlite3_malloc64( sz+(bBin==0) );
  if( p==0 ){
    sqlite3_result_error_nomem(context);
    goto edit_func_end;
  }
  if( bBin ){
    x = fread(p, 1, sz, f);
  }else{
    x = fread(p, 1, sz, f);
    p[sz] = 0;
  }
  fclose(f);
  f = 0;
  if( x!=sz ){
    sqlite3_result_error(context, "could not read back the whole file", -1);
    goto edit_func_end;
  }
  if( bBin ){
    sqlite3_result_blob(context, p, sz, sqlite3_free);
  }else{
    sqlite3_result_text(context, (const char*)p, sz, sqlite3_free);
  }
  p = 0;

edit_func_end:
  if( f ) fclose(f);
  unlink(zTempFile);
  sqlite3_free(zTempFile);
  sqlite3_free(p);
}

/*
** Save or restore the current output mode
*/
static void outputModePush(ShellState *p){
  p->modePrior = p->mode;
  memcpy(p->colSepPrior, p->colSeparator, sizeof(p->colSeparator));

#endif
    sqlite3_create_function(p->db, "shell_add_schema", 3, SQLITE_UTF8, 0,
                            shellAddSchemaName, 0, 0);
    sqlite3_create_function(p->db, "shell_module_schema", 1, SQLITE_UTF8, 0,
                            shellModuleSchema, 0, 0);
    sqlite3_create_function(p->db, "shell_putsnl", 1, SQLITE_UTF8, p,
                            shellPutsFunc, 0, 0);
    sqlite3_create_function(p->db, "edit", 1, SQLITE_UTF8, 0,
                            editFunc, 0, 0);
    sqlite3_create_function(p->db, "edit", 2, SQLITE_UTF8, 0,
                            editFunc, 0, 0);
    if( p->openMode==SHELL_OPEN_ZIPFILE ){
      char *zSql = sqlite3_mprintf(
         "CREATE VIRTUAL TABLE zip USING zipfile(%Q);", p->zDbFilename);
      sqlite3_exec(p->db, zSql, 0, 0, 0);
      sqlite3_free(zSql);
    }
  }