Haketilo

# SPDX-License-Identifier: CC0-1.0

#

# Process javascript files and resolve dependencies between them

#

# This file is part of Haketilo

#

# Copyright (C) 2021, Wojtek Kosior

#

# This program is free software: you can redistribute it and/or modify

# it under the terms of the CC0 1.0 Universal License as published by

# the Creative Commons Corporation.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# CC0 1.0 Universal License for more details.

function read_file(filename,

		   imports_state, exports_state, line, record, result) {

    imports_state = "not_started"

    exports_state = "not_started"

    do {

	result = (getline line < filename)

	if (result < 0) {

	    printf "error reading %s", filename

	    exit 1

	}

	if (imports_state == "started" &&

	    line ~ /^([[:space:]]*\*[[:space:]]+)?IMPORT[[:space:]]+[_a-zA-Z][_a-zA-Z0-9]*[[:space:]]*$/) {

	    record = line

	    sub(/^([[:space:]]*\*[[:space:]]+)?IMPORT[[:space:]]+/, "", record)

	    sub(/([[:space:]]+$)/,                                  "", record)

	    imports[filename,++import_counts[filename]] = record

	}

	if (imports_state == "started" &&

	    line ~ /^([[:space:]]*\*[[:space:]]+)?IMPORTS_END[[:space:]]*$/)

	    imports_state = "finished"

	if (imports_state == "not_started" &&

	    line ~ /^([[:space:]]*\*[[:space:]]+)?IMPORTS_START[[:space:]]*$/)

	    imports_state = "started"

	if (exports_state == "started" &&

	    line ~ /^([[:space:]]*\*[[:space:]]+)?EXPORT[[:space:]]+[_a-zA-Z][_a-zA-Z0-9]*[[:space:]]*$/) {

	    record = line

	    sub(/^([[:space:]]*\*[[:space:]]+)?EXPORT[[:space:]]+/, "", record)

	    sub(/([[:space:]]+$)/,                                  "", record)

	    if (record in exports) {

		printf "ERROR: '%s' exported by both %s and %s\n",

		    exports[record], filename > "/dev/stderr"

	    }

	    provides[record] = filename

	    exports[filename,++export_counts[filename]] = record

	}

	if (exports_state == "started" &&

	    line ~ /^([[:space:]]*\*[[:space:]]+)?EXPORTS_END[[:space:]]*$/)

	    exports_state = "finished"

	if (exports_state == "not_started" &&

	    line ~ /^([[:space:]]*\*[[:space:]]+)?EXPORTS_START[[:space:]]*$/)

	    exports_state = "started"

    } while (result > 0)

    if (imports_state == "started") {

	printf "ERROR: Unclosed IMPORTS list in '%s'\n", filename	\

	    > "/dev/stderr"

	exit 1

    }

    if (exports_state == "started") {

	printf "ERROR: Unclosed EXPORTS list in '%s'\n", filename	\

	    > "/dev/stderr"

	exit 1

    }

    close(filename)

}

function print_file(filename,    line) {

    while ((getline line < filename) > 0)

	print(line)

    close(filename)

}

function print_imports_code(filename,    i, count, import_name) {

    count = import_counts[filename]

    for (i = 1; i <= count; i++) {

	import_name = imports[filename,i]

	printf "const %s = window.killtheweb.%s;\n", import_name, import_name

    }

}

function print_exports_code(filename,    i, count, export_name) {

    count = export_counts[filename]

    for (i = 1; i <= count; i++) {

	export_name = exports[filename,i]

	printf "window.killtheweb.%s = %s;\n", export_name, export_name

    }

}

function wrap_file(filename) {

    print "\"use strict\";\n\n({fun: (function() {\n"

    print_imports_code(filename)

    printf "\n\n"

    print_file(filename)

    printf "\n\n"

    print_exports_code(filename)

    print "\n})}).fun();"

}

function compute_dependencies(filename,    i, count, import_name, next_file) {

    if (processed[filename] == "used")

	return 0

    if (processed[filename] == "on_stack") {

	printf "import loop on %s\n", filename > "/dev/stderr"

	return 1

    }

    processed[filename] = "on_stack"

    count = import_counts[filename]

    for (i = 1; i <= count; i++) {

	import_name = imports[filename,i]

	if (!(import_name in provides)) {

	    printf "nothing exports %s, required by %s\n",

		import_name, filename > "/dev/stderr"

	    return 1

	}

	if (compute_dependencies(provides[import_name]) > 0) {

	    printf "when satisfying %s for %s\n",

		import_name, filename > "/dev/stderr"

	    return 1

	}

    }

    processed[filename] = "used"

    print filename

    return 0

}

function print_usage() {

    printf "usage:  %2 compute_scripts.awk script_dependencies|wrapped_code FILENAME[...]\n",

	ARGV[0] > "/dev/stderr"

    exit 1

}

function mock_exports_init() {

    provides["browser"]    = "exports_init.js"

    provides["is_chrome"]  = "exports_init.js"

    provides["is_mozilla"] = "exports_init.js"

    processed["exports_init.js"] = "used"

}

BEGIN {

    operation = ARGV[1]

    if (ARGC < 3)

	print_usage()

    root_filename = ARGV[2]

    for (i = 2; i < ARGC; i++)

	filenames[ARGV[i]]

    mock_exports_init()

    for (filename in filenames) {

	# A filename is allowed to appear multiple times in the list.

	# Let's only process it once.

	if (!(filename in processed))

	    read_file(filename)

	processed[filename] = "not_used"

    }

    if (operation == "script_dependencies") {

	print("exports_init.js")

	if (compute_dependencies(root_filename) > 0)

	    exit 1

    } else if (operation == "wrapped_code") {

	wrap_file(root_filename)

    } else {

	print_usage()

    }

}