appjet-app-base/lib-utils/useful.js

/* appjet:version 0.1 */
// (c) 2009, Herbert Vojčík
// Licensed by MIT license (http://www.opensource.org/licenses/mit-license.php)

/* appjet:library */

/**@overview This library contains various utility functions
 * that appeared during developing other apps but are general enough.
 */

/**
 * Returns global object.
 */
function global() { return {}.valueOf.call(); }

/**
 * Returns stub function that logs arguments called
 * into its property called log and returns retval.
 * Useful primarily for testing.
 */
function stub(retval) {
    var result = function() {
        result.log.push(Array.slice(arguments));
        return retval;
    };
    result.log = [];
    return result;
}

/**
 * Read-only wrapper on an object.
 */
function readonly(o) {
    return appjet._native.createProxyObject(
        function(name) { return o[name]; },
        function() {},
        function() {},
        function() { return []; },
        o
    );
}

/**
 * Extends an object by copying all other object's own properties.
 * Returns the extended object. This implies you can create clone
 * of simple object by extend({}, x).
 */
function extend(dst, src) {
    eachProperty(src, function(p) { dst[p] = src[p]; });
    return dst;
}

/**
 * Akin to <code>Array >> streamContents:</code> in Smalltalk.
 * Calls f and returns array of every item that was printed using print.
 * Useful for collecting any item in some loop(s) for which
 * filter or map can not be straightforwardly used. Both examples get keys
 * of own properties
 @example
 collectPrint(function() { eachProperty(object, print); });
 collectPrint(function() {for (var p in object) { if (object.hasOwnProperty(p) print(p); }});
 */
function collectPrint(f) {
    var result = [];
    var _g = global();
    var savedPrint = _g.print;
    _g.print = function() { result.push.apply(result, arguments); }; // cannot inline, or f***ing try/finally bug which nobody is willing to fix appears
    try { f(); } finally { _g.print = savedPrint; }
    return result;
}

function _collector(result) { return function() { result.push.apply(result, arguments); }; }

/**
 * Akin to <code>Array >> streamContents:</code> in Smalltalk.
 * Calls f and returns array of every item that was yielded using yield.
 * Useful for collecting any item in some loop(s) for which
 * filter or map can not be straightforwardly used. An example gets keys
 * of own properties
 @example
 collectYield(function () {for (var p in object) { if (object.hasOwnProperty(p) yield p; }});
 */
function collectYield(f) {
    var result = [];
    var gen = f();
    try {
        for(;;) { result.push(gen.next()); }
    } catch (ex if ex instanceof StopIteration) {
        //gen.close(); //strange, not needed
    }
    return result;
}

//from web; then edited
/** Converts h,s,v (0-1) to rgb (0-255). Returns array [r, g, b]. */
function hsv2rgb(h,s,v) {
    // Adapted from http://www.easyrgb.com/math.html
    // hsv values = 0 - 1, rgb values = 0 - 255
    var r, g, b;
    if (s == 0) {
    	r = g = b = v;
    } else {
        var vh = 6*h;
        var vi = Math.floor(vh);
        var v1 = v*(1-s);
        var v2 = v*(1-s*(vh-vi));
        var v3 = v*(1-s*(1-(vh-vi)));
        switch(vi) {
            case 0: r = v; g = v3; b = v1; break;
            case 1: r = v2; g = v; b = v1; break;
            case 2: r = v1; g = v; b = v3; break;
            case 3: r = v1; g = v2; b = v; break;
            case 4: r = v3; g = v1; b = v; break;
            case 5: r = v; g = v1; b = v2; break;
        }
    }
    return [ Math.round(255*r), Math.round(255*g), Math.round(255*b) ];
}

/**
 * Call this function with etag of actual requested resource.
 * Includes caching headers in the response,
 * and if the ETag matches, it immediately stops the response
 * with "304 Not Modified"; in other case it returns
 * and lets you continue with populating the response data.
 * Call after you KNOW the resource exists! It is illegal
 * to change response status to 404 or similar after this call.
 */
function etagCaching(etag) {
    response.setCacheable(null);
    response.setHeader("Cache-Control", "public, must-revalidate");
    response.setHeader("ETag", etag);
    var cond = request.headers["If-None-Match"];
    if (cond && (cond === "*" || ([].concat(cond).indexOf(etag) !== -1))) {
        response.setStatusCode(304);
        response.stop();
    }
}

/* appjet:server */
import("lib-utils/jsunit");
var _l = import({}, "lib-utils/useful");

// ==== Test cases ====

page.testSuite = [

	function collectPrintCollectsPrintedArguments() {
	    var collected = _l.collectPrint(function() {
	        print("Hello", "world", "!");
	        print();
	        print(3,1,4);
	    });
	    assertArrayEquals("Incorrect items collected.", ["Hello", "world", "!", 3, 1, 4], collected);
	},
	
	function collectPrintRetainsLegacyPrint() {
	    var savedPrint = this.print;
	    _l.collectPrint(function() {
	        print("Hello", "world", "!");
	        print();
	        print(3,1,4);
	    });
	    assertEquals("Print not retained.", savedPrint, this.print);
	},
	
	function collectPrintRetainsLegacyPrintInCaseOfException() {
	    var savedPrint = this.print;
	    var f = function() { throw "exception"; };
	    try {
	        _l.collectPrint(f);
	        fail("Exception not thrown");
	    } catch(ex if ex === "exception") {
	        // pass
	    }
	    assertEquals("Print not retained.", savedPrint, this.print);
	},
	
	function collectPrintRetainsLegacyPrintInCaseOfUndefinedException() {
	    var savedPrint = this.print;
	    var f = function() { throw undefined; };
	    try {
	        _l.collectPrint(f);
	        fail("Exception not thrown");
	    } catch(ex if ex === undefined) {
	        // pass
	    }
	    assertEquals("Print not retained.", savedPrint, this.print);
	},
	
	function collectYieldCollectsYieldedArguments() {
	    var collected = _l.collectYield(function() {
	        yield "Hello";
	        yield 3;
	    });
	    assertArrayEquals("Incorrect items collected.", ["Hello", 3], collected);
	},
	
	function collectYieldCollectsYieldeesFromTryBlockAndFinallyRuns() {
	    var frun = false;
	    var collected = _l.collectYield(function() {
	        try {
	            yield "Hello";
	            yield 3;
	        } finally { frun = true; }
	    });
	    assertArrayEquals("Incorrect items collected.", ["Hello", 3], collected);
	    assertTrue("Finally did not run", frun);
	},
	
	function collectYieldThrowsExceptionIfThrownInF() {
	    try {
	        var collected = _l.collectYield(function() {
	            yield "Hello";
	            throw "exception";
	            yield "world";
	        });
	        fail("Exception not thrown.");
	    } catch(ex if ex === "exception") {
	        // pass
	    }
	},
	
	function collectYieldThrowsUndefinedIfThrownInF() {
	    try {
	        var collected = _l.collectYield(function() {
	            yield "Hello";
	            throw undefined;
	            yield "world";
	        });
	        fail("Exception not thrown.");
	    } catch(ex if ex === undefined) {
	        // pass
	    }
	},
	
	function collectYieldThrowsExceptionIfExceptionThrownInF_AndFinallyInFRuns() {
	    var finallyRun = false;
	    try {
	        var collected = _l.collectYield(function() {
	            try {
	                yield "Hello";
	                throw "exception";
	                yield "world";
	            } finally { finallyRun = true; }
	        });
	        fail("Exception not thrown.");
	    } catch(ex if ex === "exception") {
	        // pass
	    }
	    assertTrue("Finally in f did not run.", finallyRun);
	},
	
	function readonlyReadsCorrectlyAndIsDynamic() {
	    var x = {hello: "world"};
	    var rx = _l.readonly(x);
	    assertEquals("Hello read incorrectly", "world", rx.hello);
	    assertUndefined("Nonexistent property is not undefined", rx.thisIsNot);
	    x.hello = "again";
	    x.thisIsNot = "this is";
	    assertEquals("Hello read incorrectly", "again", rx.hello);
	    assertEquals("ThisIsNot read incorrectly", "this is", rx.thisIsNot);
	},
	
	function readonlyIsReadOnly() {
	    var x = {hello: "world"};
	    var rx = _l.readonly(x);
	    rx.thisIsNot = "this is";
	    delete rx.hello;
	    assertEquals("Hello read incorrectly", "world", rx.hello);
	    assertUndefined("Nonexistent property is not undefined", rx.thisIsNot);
	},
	
	function extendExtendsCorrectlyForAllCombinations() {
	    var srcProto = { pro: "to" }
	    var src = object(srcProto);
	    src.a = "b"; src.c = "d";
	    var dst = { pro: "fi", a: "bc", yes: "true" };
	    var result = _l.extend(dst, src);
	    assertEquals("extend did not return extended object", dst, result);
	    assertEquals("a wasn't copied", "b", dst.a);
	    assertEquals("c wasn't copied", "d", dst.c);
	    assertEquals("pro was changed", "fi", dst.pro);
	    assertEquals("yes was changed", "true", dst.yes);
	},
	
	function logIsEmptyForNewStub() {
	    var f = _l.stub();
	    assertArrayEquals("Log is not empty array", [], f.log);
	},
	
	function stubIsAFunction() {
	    var f = _l.stub();
	    assertEquals("Stub is not a function", "function", typeof f);
	},
	
	function stubWithoutRetvalReturnsUndefined() {
	    var f = _l.stub();
	    assertEquals("Stub doesn't return undefined", undefined, f(3, "hello"));
	},
	
	function stubWithRetvalReturnsRetval() {
	    var f = _l.stub("world");
	    assertEquals("Stub returns incorrect value", "world", f(3, "hello"));
	},
	
	function stub_CalledMultipleTimes_ReturnsAlwaysRetval_AndLogsArguments() {
	    var f = _l.stub("hi");
	    var r1 = f("hello", 14, "world");
	    assertArrayEquals("Log is incorrect 1", [["hello", 14, "world"]], f.log);
	    var r2 = f("!", f);
	    assertArrayEquals("Log is incorrect 2", [["hello", 14, "world"], ["!", f]], f.log);
	    f();
	    assertArrayEquals("Log is incorrect 3", [["hello", 14, "world"], ["!", f], []], f.log);
	    assertEquals("Stub returns incorrect value 1", "hi", r1);
	    assertEquals("Stub returns incorrect value 2", "hi", r2);
	},

];

// ==== Test runner ====
import("lib-utils/runner");
runTestsByDefault();