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/* Copyright (c) 2002-2018 Pigeonhole authors, see the included COPYING file
*/
#include "sieve-common.h"
#include "sieve-commands.h"
#include "sieve-validator.h"
#include "sieve-generator.h"
#include "sieve-code.h"
#include "sieve-binary.h"
/*
* Commands
*/
static bool cmd_if_validate
(struct sieve_validator *valdtr, struct sieve_command *cmd);
static bool cmd_elsif_validate
(struct sieve_validator *valdtr, struct sieve_command *cmd);
static bool cmd_if_validate_const
(struct sieve_validator *valdtr, struct sieve_command *cmd,
int *const_current, int const_next);
static bool cmd_if_generate
(const struct sieve_codegen_env *cgenv, struct sieve_command *cmd);
static bool cmd_else_generate
(const struct sieve_codegen_env *cgenv, struct sieve_command *cmd);
/* If command
*
* Syntax:
* if <test1: test> <block1: block>
*/
const struct sieve_command_def cmd_if = {
.identifier = "if",
.type = SCT_COMMAND,
.positional_args = 0,
.subtests = 1,
.block_allowed = TRUE,
.block_required = TRUE,
.validate = cmd_if_validate,
.validate_const = cmd_if_validate_const,
.generate = cmd_if_generate
};
/* ElsIf command
*
* Santax:
* elsif <test2: test> <block2: block>
*/
const struct sieve_command_def cmd_elsif = {
.identifier = "elsif",
.type = SCT_COMMAND,
.positional_args = 0,
.subtests = 1,
.block_allowed = TRUE,
.block_required = TRUE,
.validate = cmd_elsif_validate,
.validate_const = cmd_if_validate_const,
.generate = cmd_if_generate
};
/* Else command
*
* Syntax:
* else <block>
*/
const struct sieve_command_def cmd_else = {
.identifier = "else",
.type = SCT_COMMAND,
.positional_args = 0,
.subtests = 0,
.block_allowed = TRUE,
.block_required = TRUE,
.validate = cmd_elsif_validate,
.validate_const = cmd_if_validate_const,
.generate = cmd_else_generate
};
/*
* Context management
*/
struct cmd_if_context_data {
struct cmd_if_context_data *previous;
struct cmd_if_context_data *next;
int const_condition;
bool jump_generated;
sieve_size_t exit_jump;
};
static void cmd_if_initialize_context_data
(struct sieve_command *cmd, struct cmd_if_context_data *previous)
{
struct cmd_if_context_data *cmd_data;
/* Assign context */
cmd_data = p_new(sieve_command_pool(cmd), struct cmd_if_context_data, 1);
cmd_data->exit_jump = 0;
cmd_data->jump_generated = FALSE;
/* Update linked list of contexts */
cmd_data->previous = previous;
cmd_data->next = NULL;
if ( previous != NULL )
previous->next = cmd_data;
/* Check const status */
cmd_data->const_condition = -1;
while ( previous != NULL ) {
if ( previous->const_condition > 0 ) {
cmd_data->const_condition = 0;
break;
}
previous = previous->previous;
}
/* Assign to command context */
cmd->data = cmd_data;
}
/*
* Validation
*/
static bool cmd_if_validate
(struct sieve_validator *valdtr ATTR_UNUSED, struct sieve_command *cmd)
{
/* Start if-command structure */
cmd_if_initialize_context_data(cmd, NULL);
return TRUE;
}
static bool cmd_elsif_validate
(struct sieve_validator *valdtr, struct sieve_command *cmd)
{
struct sieve_command *prev;
i_assert(cmd != NULL);
prev = sieve_command_prev(cmd);
/* Check valid command placement */
if ( prev == NULL ||
( !sieve_command_is(prev, cmd_if) && !sieve_command_is(prev, cmd_elsif) ) )
{
sieve_command_validate_error(valdtr, cmd,
"the %s command must follow an if or elseif command",
sieve_command_identifier(cmd));
return FALSE;
}
/* Previous command in this block is 'if' or 'elsif', so we can safely refer
* to its context data
*/
cmd_if_initialize_context_data(cmd, prev->data);
return TRUE;
}
static bool cmd_if_validate_const
(struct sieve_validator *valdtr ATTR_UNUSED, struct sieve_command *cmd,
int *const_current, int const_next)
{
struct cmd_if_context_data *cmd_data =
(struct cmd_if_context_data *) cmd->data;
if ( cmd_data != NULL ) {
if ( cmd_data->const_condition == 0 ) {
*const_current = cmd_data->const_condition;
return FALSE;
}
cmd_data->const_condition = const_next;
}
*const_current = const_next;
return ( const_next < 0 );
}
/*
* Code generation
*/
/* The if command does not generate specific IF-ELSIF-ELSE opcodes, but only uses
* JMP instructions. This is why the implementation of the if command does not
* include an opcode implementation.
*/
static void cmd_if_resolve_exit_jumps
(struct sieve_binary_block *sblock, struct cmd_if_context_data *cmd_data)
{
struct cmd_if_context_data *if_ctx = cmd_data->previous;
/* Iterate backwards through all if-command contexts and resolve the
* exit jumps to the current code position.
*/
while ( if_ctx != NULL ) {
if ( if_ctx->jump_generated )
sieve_binary_resolve_offset(sblock, if_ctx->exit_jump);
if_ctx = if_ctx->previous;
}
}
static bool cmd_if_generate
(const struct sieve_codegen_env *cgenv, struct sieve_command *cmd)
{
struct sieve_binary_block *sblock = cgenv->sblock;
struct cmd_if_context_data *cmd_data =
(struct cmd_if_context_data *) cmd->data;
struct sieve_ast_node *test;
struct sieve_jumplist jmplist;
/* Generate test condition */
if ( cmd_data->const_condition < 0 ) {
/* Prepare jumplist */
sieve_jumplist_init_temp(&jmplist, sblock);
test = sieve_ast_test_first(cmd->ast_node);
if ( !sieve_generate_test(cgenv, test, &jmplist, FALSE) )
return FALSE;
}
/* Case true { */
if ( cmd_data->const_condition != 0 ) {
if ( !sieve_generate_block(cgenv, cmd->ast_node) )
return FALSE;
}
/* Are we the final command in this if-elsif-else structure? */
if ( cmd_data->next == NULL || cmd_data->const_condition == 1 ) {
/* Yes, Resolve previous exit jumps to this point */
cmd_if_resolve_exit_jumps(sblock, cmd_data);
} else if ( cmd_data->const_condition < 0 ) {
/* No, generate jump to end of if-elsif-else structure (resolved later)
* This of course is not necessary if the {} block contains a command
* like stop at top level that unconditionally exits the block already
* anyway.
*/
if ( !sieve_command_block_exits_unconditionally(cmd) ) {
sieve_operation_emit(sblock, NULL, &sieve_jmp_operation);
cmd_data->exit_jump = sieve_binary_emit_offset(sblock, 0);
cmd_data->jump_generated = TRUE;
}
}
if ( cmd_data->const_condition < 0 ) {
/* Case false ... (subsequent elsif/else commands might generate more) */
sieve_jumplist_resolve(&jmplist);
}
return TRUE;
}
static bool cmd_else_generate
(const struct sieve_codegen_env *cgenv, struct sieve_command *cmd)
{
struct cmd_if_context_data *cmd_data =
(struct cmd_if_context_data *) cmd->data;
/* Else { */
if ( cmd_data->const_condition != 0 ) {
if ( !sieve_generate_block(cgenv, cmd->ast_node) )
return FALSE;
/* } End: resolve all exit blocks */
cmd_if_resolve_exit_jumps(cgenv->sblock, cmd_data);
}
return TRUE;
}
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