Python script to remove include guards from files. It also leaves files with exactly one trailing newline.

unifdef.py

#! /usr/bin/env python3


import sys, os

def main(args):

    if len(args) < 2:
        print("./unifdef file1.h file2.h..")
        print("Python script to remove include guards from files, and replaces with '#pragma once'.")
        print("It also leaves files with exactly one trailing newline.")
        print("Use globs with something like zsh to provide lots of arguments")
        print("Example: ./unifdef.py Client/**/**.h<tab>")
        return
    
    files = args[1:]
    for f in files:
        if not os.path.isfile(f):
            print("{} is not a file".format(f))
            continue

        process(f)

def process(filepath):
    # print("Reading", filepath)
    file = open(filepath, "r")

    previousLine = ""
    lastLine = -1

    fileContent = file.read()
    lineFeed = file.newlines

    newLines = list(fileContent.splitlines())

    
    define = None

    for i, l in enumerate(newLines):
        l = l + lineFeed
        newLines[i] = l


        if not define and previousLine != "" and l == previousLine:
            define = (previousLine[len("#define "):].strip(), i)
            print("Found", filepath, define)

        if define:
            if l.strip() != "":
                previousLine = l
                lastLine = i
        else:
            # only read thirty lines to check for defines
            if i >= 30:
                break

            if l.startswith("#ifndef "):
                previousLine = l.replace("#ifndef ", "#define ")
                # print(previousLine)
                # print(l)
            else:
                previousLine = ""
                define = ""
    # print(newLines)
    previousLine = previousLine.strip()
    if define and previousLine == "#endif":
        # Drop this line from the list
        linesToDrop = [lastLine, define[1], define[1]-1]
        if sorted(linesToDrop, reverse=True) != linesToDrop or any(map(lambda x: x < 0, linesToDrop)):
            print("Encountered line parity error with {}, lines are {}", filepath, linesToDrop)
        else:
            print("Done", filepath, previousLine, len(previousLine), lastLine)
            
            newLines[define[1]-1] = "#pragma once" + lineFeed
            newLines[define[1]] = ""

            # if lastLine == len(newLines):
            #     newLines[lastLine] = lineFeed # last line should be a newline
            # else:
            newLines[lastLine] = ""

            # Check last couple of lines to ensure that there is exactly one newline at end
            trueLastLine = len(newLines) - 1
            startLine = -1
            for i in range(trueLastLine-5, len(newLines)):
                if startLine == -1 and newLines[i].strip() == "":
                    startLine = i
                elif newLines[i].strip() != "":
                    startLine = -1
            
            if startLine != -1:
                print(startLine, len(newLines))
                for i in range(startLine, len(newLines)):
                    newLines[i] = ""

            file.close()
            file = open(filepath, "w")

            file.write("".join(newLines))
            print("")
    # print(newLines)

    file.close()

if __name__ == "__main__":
    main(sys.argv)