1 files changed, 277 insertions, 0 deletions
diff --git a/pigeonhole/src/lib-sieve/cmd-if.c b/pigeonhole/src/lib-sieve/cmd-if.c
new file mode 100644
index 0000000..2ae186e
--- /dev/null
+++ b/pigeonhole/src/lib-sieve/cmd-if.c
@@ -0,0 +1,277 @@
+/* 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;
+}
+