clcp

// This program moniters the clipboard / primary (mouse selection) buffers
// and prints text or runs a command on change.
//
// The goals of this project:
//
//	1. < 100 lines code
//	2. Simple & elegant coding
//	3. Fast & efficient execution.
//
//		"Do one thing,
//		 and do it well."
//
//		—Linux Credo
//
// Credits:
// https://stackoverflow.com/questions/27378318/c-get-string-from-clipboard-on-linux
// https://cboard.cprogramming.com/c-programming/63166-kbhit-linux.html
// https://www.unix.com/
//
// Compile with:
// $ g++ -O -Wall clcp.cpp -o clcp -lX11 -std=c++17
//
// Print clipboard buffer text to screen and wait 1000 milliseconds
// to check again:
// $ clcp -c 1000
//
// Run output of clipboard buffer as a command then exit immediately
// (a '0' tells the program to exit and not wait and grab more input):
// $ clcp -c -e 'midori https://duckduckgo.com/?q=%clip%' 0
//
// Where the command ran would be (if the word 'debian' were to have
// been selected by the mouse):
// $ midori https://duckduckgo.com/?q=debian
//
// Print to screen (default) what is mouse selected and check buffers
// every 500ms (default) for a change:
// $ clcp
//
// Use with UTF-8 instead of regular string. This is helpful when using
// characters with macrons and other characters of this kind:
// $ clcp -u
//
// Press any key to exit program.
//
// github: https://gist.github.com/bathtime/39502e6ae6524a4fc37cb55f4d5459fa
//
// Feel free to fork or make contributions, but if you contribute, and I
// very much welcome it :), please remove a line of code for every
// line you add by making the code more efficient; the program must not
// exceed 200 code lines (or the world explodes).
//

#include<experimental/string_view>
#include<algorithm>
#include<string.h>
#include<iostream>
#include<limits.h>
#include<X11/Xlib.h>
#include<chrono>
#include<thread>
#include<termios.h>
#include<unistd.h>
#include<sys/time.h>
#include<sys/types.h>
#include<stdio.h>
#include<termios.h>
#include<unistd.h>
#include<fcntl.h>

// Function to capture clipboard buffers
std::string PrintSelection(Display *display, Window & window, const char *bufname, const char *fmtname, std::string text)
{
	char *result;
	unsigned long ressize, restail;
	int resbits;
	Atom bufid	= XInternAtom(display, bufname, False),
	fmtid		= XInternAtom(display, fmtname, False),
	propid 		= XInternAtom(display, "XSEL_DATA", False),
	incrid		= XInternAtom(display, "INCR", False);
	XEvent event;

	XConvertSelection(display, bufid, fmtid, propid, window, CurrentTime);

	do
		XNextEvent(display, &event);
	while (event.type != SelectionNotify || event.xselection.selection != bufid);

	if (event.xselection.property)
	{
		XGetWindowProperty(display, window, propid, 0, LONG_MAX/4, False, AnyPropertyType, &fmtid, &resbits, &ressize, &restail, (unsigned char**)&result);

		if (fmtid == incrid)
			printf("Buffer is too large and INCR reading is not implemented yet.\n");
		else {

			std::string clpWrd = "%clip%";

			// Replace clpWrd with buffer contents
			std::size_t pos = text.find(clpWrd);

			if (pos != std::string::npos)
                        	text = text.substr(0, pos) + result + text.substr(pos + clpWrd.length(), text.length());
                	else
				text += result;
		}

		XFree(result);

		return text;

	} else{	// request failed, e.g. owner can't convert to the target format
		std::cout << "No buffered content. Please fill buffer." << std::endl;
		return "";
	}
}

// Capture keyboard input

void changemode(int);
int  kbhit(void);

void changemode(int dir)
{
	static struct termios oldt, newt;

	if ( dir == 1 )
	{
		tcgetattr( STDIN_FILENO, &oldt);
		newt = oldt;
		newt.c_lflag &= ~( ICANON | ECHO );
		tcsetattr( STDIN_FILENO, TCSANOW, &newt);
	} else
		tcsetattr( STDIN_FILENO, TCSANOW, &oldt);
}

// Keyboard input
int kbhit (void)
{
	struct timeval tv;
	fd_set rdfs;

	tv.tv_sec = 0;
	tv.tv_usec = 0;

	FD_ZERO(&rdfs);
	FD_SET (STDIN_FILENO, &rdfs);

	select(STDIN_FILENO+1, &rdfs, NULL, NULL, &tv);

	return FD_ISSET(STDIN_FILENO, &rdfs);
}

using namespace std;

int main(int argc, char* argv[]) {

	// Set defaults if they are not entered as parameters
	std::string line 	= "";		// Text to be printed/manipulated
	std::string tmpStr	= "";
	const char * strType	= "STRING";	// STRING  or UTF8_STRING
	const char * clpType	= "PRIMARY";	// PRIMARY or CLIPBOARD
        bool isExec             = 0;            // Default to print text, not execute
        long milSec             = 500;          // Miliseconds for thread sleep

	// Sort out parameters and set variables
        for(int pNum = 1; pNum < argc; pNum++) {

		tmpStr = argv[pNum];

		// First check if it is a number. Use new efficient string_view func :)
		if (!std::experimental::string_view(argv[pNum]).empty() && std::all_of(tmpStr.begin(), tmpStr.end(), ::isdigit))
			milSec	= stoi(argv[pNum]);
		else if (std::experimental::string_view(argv[pNum]) == "-c")
			clpType = "CLIPBOARD";
		else if (std::experimental::string_view(argv[pNum]) == "-u")
                        strType = "UTF8_STRING";
		else if (std::experimental::string_view(argv[pNum]) == "-e")
			isExec 	= 1;
		else	// Just append other stuff to text (quoted or unquated)
			line += argv[pNum];
	}

	// Buffer capture variables
	Display *display	= XOpenDisplay(NULL);
	unsigned long color	= BlackPixel(display, DefaultScreen(display));
	Window window		= XCreateSimpleWindow(display, DefaultRootWindow(display), 0,0, 1,1, 0, color, color);

	changemode(1);		// keyboard input

	std::string lastClip;
        std::chrono::milliseconds timespan(milSec);

	// Let's roll whilst no key is pressed!
	while (!kbhit()){

		// Gather all the output info
		std::string result = PrintSelection(display, window, clpType, strType, line);

		if (result != lastClip)
		{
			lastClip = result;

		        if (isExec)			// Execute or print to screen?
				system(result.c_str());
			else
        		        std::cout << result << std::endl;

			if (milSec == 0) return 0;	// Just run once and exit.
		}

		// Sleep in an efficient manner
		std::this_thread::sleep_for(timespan);
	}

	// Buffer capture shutting down commands
	XDestroyWindow(display, window);
	XCloseDisplay(display);

	changemode(1);		// Keyboard input. Change back to regular mode.

	return 0;
}