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Diffstat (limited to 'src/grep_proc.hh')
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diff --git a/src/grep_proc.hh b/src/grep_proc.hh new file mode 100644 index 0000000..58010e3 --- /dev/null +++ b/src/grep_proc.hh @@ -0,0 +1,307 @@ +/** + * Copyright (c) 2007-2012, Timothy Stack + * + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * * Redistributions of source code must retain the above copyright notice, this + * list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * * Neither the name of Timothy Stack nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY + * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * @file grep_proc.hh + */ + +#ifndef grep_proc_hh +#define grep_proc_hh + +#include <deque> +#include <exception> +#include <string> +#include <vector> + +#include <poll.h> +#include <stdio.h> +#include <sys/types.h> +#include <unistd.h> + +#include "base/auto_fd.hh" +#include "base/auto_mem.hh" +#include "base/lnav_log.hh" +#include "line_buffer.hh" +#include "pcrepp/pcre2pp.hh" +#include "pollable.hh" +#include "strong_int.hh" + +template<typename LineType> +class grep_proc; + +/** + * Data source for lines to be searched using a grep_proc. + */ +template<typename LineType> +class grep_proc_source { +public: + virtual ~grep_proc_source() = default; + + virtual void register_proc(grep_proc<LineType>* proc) + { + this->gps_proc = proc; + } + + /** + * Get the value for a particular line in the source. + * + * @param line The line to retrieve. + * @param value_out The destination for the line value. + */ + virtual bool grep_value_for_line(LineType line, std::string& value_out) = 0; + + virtual LineType grep_initial_line(LineType start, LineType highest) + { + if (start == -1) { + return highest; + } + return start; + } + + virtual void grep_next_line(LineType& line) { line = line + LineType(1); } + + grep_proc<LineType>* gps_proc; +}; + +/** + * Delegate interface for control messages from the grep_proc. + */ +class grep_proc_control { +public: + virtual ~grep_proc_control() = default; + + /** @param msg The error encountered while attempting the grep. */ + virtual void grep_error(const std::string& msg) {} +}; + +/** + * Sink for matches produced by a grep_proc instance. + */ +template<typename LineType> +class grep_proc_sink { +public: + virtual ~grep_proc_sink() = default; + + virtual void grep_quiesce() {} + + /** Called at the start of a new grep run. */ + virtual void grep_begin(grep_proc<LineType>& gp, + LineType start, + LineType stop) + { + } + + /** Called periodically between grep_begin and grep_end. */ + virtual void grep_end_batch(grep_proc<LineType>& gp) {} + + /** Called at the end of a grep run. */ + virtual void grep_end(grep_proc<LineType>& gp) {} + + /** + * Called when a match is found on 'line' and between [start, end). + * + * @param line The line number that matched. + * @param start The offset within the line where the match begins. + * @param end The offset of the character after the last character in the + * match. + */ + virtual void grep_match(grep_proc<LineType>& gp, + LineType line, + int start, + int end) + = 0; + + /** + * Called for each captured substring in the line. + * + * @param line The line number that matched. + * @param start The offset within the line where the capture begins. + * @param end The offset of the character after the last character in the + * capture. + * @param capture The captured substring itself. + */ + virtual void grep_capture(grep_proc<LineType>& gp, + LineType line, + int start, + int end, + char* capture){}; + + virtual void grep_match_end(grep_proc<LineType>& gp, LineType line){}; +}; + +/** + * "Grep" that runs in a separate process so it doesn't stall user-interaction. + * This class manages the child process and any interactions between the parent + * and child. The source data to be matched comes from the grep_proc_source + * delegate and the results are sent to the grep_proc_sink delegate in the + * parent process. + * + * Note: The "grep" executable is not actually used, instead we use the pcre(3) + * library directly. + */ +template<typename LineType> +class grep_proc : public pollable { +public: + class error : public std::exception { + public: + error(int err) : e_err(err){}; + + int e_err; + }; + + /** + * Construct a grep_proc object. You must call the start() method + * to fork off the child process and begin processing. + * + * @param code The pcre code to run over the lines of input. + * @param gps The source of the data to match. + */ + grep_proc(std::shared_ptr<lnav::pcre2pp::code> code, + grep_proc_source<LineType>& gps, + std::shared_ptr<pollable_supervisor> ps); + + grep_proc(std::shared_ptr<pollable_supervisor>); + + using injectable = grep_proc(std::shared_ptr<pollable_supervisor>); + + virtual ~grep_proc(); + + /** @param gpd The sink to send results to. */ + void set_sink(grep_proc_sink<LineType>* gpd) { this->gp_sink = gpd; } + + grep_proc& invalidate(); + + /** @param gpc The control to send results to. */ + void set_control(grep_proc_control* gpc) { this->gp_control = gpc; } + + /** @return The sink to send results to. */ + grep_proc_sink<LineType>* get_sink() { return this->gp_sink; } + + /** + * Queue a request to search the input between the given line numbers. + * + * @param start The line number to start the search at. + * @param stop The line number to stop the search at (exclusive) or -1 to + * read until the end-of-file. + */ + grep_proc& queue_request(LineType start = LineType(0), + LineType stop = LineType(-1)) + { + require(start != -1 || stop == -1); + require(stop == -1 || start < stop); + + this->gp_queue.emplace_back(start, stop); + if (this->gp_sink) { + this->gp_sink->grep_begin(*this, start, stop); + } + + return *this; + } + + /** + * Start the search requests that have been queued up with queue_request. + */ + void start(); + + void update_poll_set(std::vector<struct pollfd>& pollfds) override; + + /** + * Check the fd_set to see if there is any new data to be processed. + * + * @param ready_rfds The set of ready-to-read file descriptors. + */ + void check_poll_set(const std::vector<struct pollfd>& pollfds) override; + + /** Check the invariants for this object. */ + bool invariant() + { + if (this->gp_child_started) { + require(this->gp_child > 0); + require(this->gp_line_buffer.get_fd() != -1); + } else { + /* require(this->gp_child == -1); XXX doesnt work with static destr + */ + require(this->gp_line_buffer.get_fd() == -1); + } + + return true; + } + +protected: + /** + * Dispatch a line received from the child. + */ + void dispatch_line(char* line); + + /** + * Free any resources used by the object and make sure the child has been + * terminated. + */ + void cleanup(); + + void child_loop(); + + virtual void child_init(){}; + + virtual void child_batch() { fflush(stdout); } + + virtual void child_term() { fflush(stdout); } + + virtual void handle_match( + int line, std::string& line_value, int off, int* matches, int count); + + std::shared_ptr<lnav::pcre2pp::code> gp_pcre; + grep_proc_source<LineType>& gp_source; /*< The data source delegate. */ + + auto_fd gp_err_pipe; /*< Standard error from the child. */ + line_buffer gp_line_buffer; /*< Standard out from the child. */ + file_range gp_pipe_range; + + pid_t gp_child{-1}; /*< + * The child's pid or zero in the + * child. + */ + bool gp_child_started{false}; /*< True if the child was start()'d. */ + size_t gp_child_queue_size{0}; + + /** The queue of search requests. */ + std::deque<std::pair<LineType, LineType> > gp_queue; + LineType gp_last_line{0}; /*< + * The last line number received from + * the child. For multiple matches, + * the line number is only sent once. + */ + LineType gp_highest_line; /*< The highest numbered line processed + * by the grep child process. This + * value is used when the start line + * for a queued request is -1. + */ + grep_proc_sink<LineType>* gp_sink{nullptr}; /*< The sink delegate. */ + grep_proc_control* gp_control{nullptr}; /*< The control delegate. */ +}; + +#endif |