fish-shell/src/parse_execution.h

// Provides the "linkage" between a parse_node_tree_t and actual execution structures (job_t, etc.).
#ifndef FISH_PARSE_EXECUTION_H
#define FISH_PARSE_EXECUTION_H

#include <stddef.h>

#include <stdbool.h>
#include "common.h"
#include "io.h"
#include "parse_constants.h"
#include "parse_tree.h"
#include "proc.h"

class parser_t;
struct block_t;

enum parse_execution_result_t {
    /// The job was successfully executed (though it have failed on its own).
    parse_execution_success,
    /// The job did not execute due to some error (e.g. failed to wildcard expand). An error will
    /// have been printed and proc_last_status will have been set.
    parse_execution_errored,
    /// The job was cancelled (e.g. Ctrl-C).
    parse_execution_cancelled,
    /// The job was skipped (e.g. due to a not-taken 'and' command). This is a special return
    /// allowed only from the populate functions, not the run functions.
    parse_execution_skipped
};

class parse_execution_context_t {
   private:
    const parse_node_tree_t tree;
    const wcstring src;
    io_chain_t block_io;
    parser_t *const parser;
    // parse_error_list_t errors;
    int eval_level;
    // The currently executing node index, used to indicate the line number.
    node_offset_t executing_node_idx;
    // Cached line number information.
    size_t cached_lineno_offset;
    int cached_lineno_count;
    // No copying allowed.
    parse_execution_context_t(const parse_execution_context_t &);
    parse_execution_context_t &operator=(const parse_execution_context_t &);

    // Should I cancel?
    bool should_cancel_execution(const block_t *block) const;

    // Ways that we can stop executing a block. These are in a sort of ascending order of
    // importance, e.g. `exit` should trump `break`.
    enum execution_cancellation_reason_t {
        execution_cancellation_none,
        execution_cancellation_loop_control,
        execution_cancellation_skip,
        execution_cancellation_exit
    };
    execution_cancellation_reason_t cancellation_reason(const block_t *block) const;

    // Report an error. Always returns true.
    parse_execution_result_t report_error(const parse_node_t &node, const wchar_t *fmt, ...) const;
    parse_execution_result_t report_errors(const parse_error_list_t &errors) const;

    // Wildcard error helper.
    parse_execution_result_t report_unmatched_wildcard_error(
        const parse_node_t &unmatched_wildcard);

    /// Command not found support.
    parse_execution_result_t handle_command_not_found(const wcstring &cmd,
                                                      const parse_node_t &statement_node,
                                                      int err_code);

    // Utilities
    wcstring get_source(const parse_node_t &node) const;
    const parse_node_t *get_child(const parse_node_t &parent, node_offset_t which,
                                  parse_token_type_t expected_type = token_type_invalid) const;
    node_offset_t get_offset(const parse_node_t &node) const;
    const parse_node_t *infinite_recursive_statement_in_job_list(const parse_node_t &job_list,
                                                                 wcstring *out_func_name) const;

    /// Indicates whether a job is a simple block (one block, no redirections).
    bool job_is_simple_block(const parse_node_t &node) const;

    enum process_type_t process_type_for_command(const parse_node_t &plain_statement,
                                                 const wcstring &cmd) const;

    // These create process_t structures from statements.
    parse_execution_result_t populate_job_process(job_t *job, process_t *proc,
                                                  const parse_node_t &statement_node);
    parse_execution_result_t populate_boolean_process(job_t *job, process_t *proc,
                                                      const parse_node_t &bool_statement);
    parse_execution_result_t populate_plain_process(job_t *job, process_t *proc,
                                                    const parse_node_t &statement);
    parse_execution_result_t populate_block_process(job_t *job, process_t *proc,
                                                    const parse_node_t &statement_node);

    // These encapsulate the actual logic of various (block) statements.
    parse_execution_result_t run_block_statement(const parse_node_t &statement);
    parse_execution_result_t run_for_statement(const parse_node_t &header,
                                               const parse_node_t &contents);
    parse_execution_result_t run_if_statement(const parse_node_t &statement);
    parse_execution_result_t run_switch_statement(const parse_node_t &statement);
    parse_execution_result_t run_while_statement(const parse_node_t &header,
                                                 const parse_node_t &contents);
    parse_execution_result_t run_function_statement(const parse_node_t &header,
                                                    const parse_node_t &block_end_command);
    parse_execution_result_t run_begin_statement(const parse_node_t &header,
                                                 const parse_node_t &contents);

    enum globspec_t { failglob, nullglob };
    parse_execution_result_t determine_arguments(const parse_node_t &parent,
                                                 wcstring_list_t *out_arguments,
                                                 globspec_t glob_behavior);

    // Determines the IO chain. Returns true on success, false on error.
    bool determine_io_chain(const parse_node_t &statement, io_chain_t *out_chain);

    parse_execution_result_t run_1_job(const parse_node_t &job_node,
                                       const block_t *associated_block);
    parse_execution_result_t run_job_list(const parse_node_t &job_list_node,
                                          const block_t *associated_block);
    parse_execution_result_t populate_job_from_job_node(job_t *j, const parse_node_t &job_node,
                                                        const block_t *associated_block);

    // Returns the line number of the node at the given index, indexed from 0. Not const since it
    // touches cached_lineno_offset.
    int line_offset_of_node_at_offset(node_offset_t idx);
    int line_offset_of_character_at_offset(size_t char_idx);

   public:
    parse_execution_context_t(moved_ref<parse_node_tree_t> t, const wcstring &s, parser_t *p,
                              int initial_eval_level);

    /// Returns the current eval level.
    int current_eval_level() const { return eval_level; }

    /// Returns the current line number, indexed from 1. Not const since it touches
    /// cached_lineno_offset.
    int get_current_line_number();

    /// Returns the source offset, or -1.
    int get_current_source_offset() const;

    /// Returns the source string.
    const wcstring &get_source() const { return src; }

    /// Start executing at the given node offset. Returns 0 if there was no error, 1 if there was an
    /// error.
    parse_execution_result_t eval_node_at_offset(node_offset_t offset,
                                                 const block_t *associated_block,
                                                 const io_chain_t &io);
};

#endif