Sweeping refactor to check CheckStyle boxes

1 files changed, 220 insertions, 148 deletions

diff --git a/src/main/model/css/CssParser.java b/src/main/model/css/CssParser.java
index 8d57bdc..25b6752 100644
--- a/src/main/model/css/CssParser.java
+++ b/src/main/model/css/CssParser.java
@@ -14,13 +14,6 @@ import java.util.*;
  * ATTRIBUTE ::= 'color' | 'text' | ...
  * VALUE ::= ??? idk lol
  */
-
-/**
- * This class assumes that it is getting _valid CSS_: that is, the style between two tags
- * of a style block, or the raw content of a .css file.
- * Making sure this assumption holds is extremely important for program robustness.
- * We do not check for validity, i.e. throw any exceptions - the driving principle of web standards is to "fail softly".
- */
 public class CssParser {
 
     /**
@@ -32,156 +25,60 @@ public class CssParser {
         SINGLE_QUOTES, DOUBLE_QUOTES, // VALUE::SINGLE_QUOTES, VALUE::DOUBLE_QUOTES
     }
 
+    // essentially the csstree type, only we don't need it to be a tree
+    private ArrayList<Pair<String, ArrayList<Pair<String, String>>>> result;
+    // a bunch of useful buffers: optimizations in the future could likely come from tweaking these
+    // note that i know nothing about data structure performance: but i'm pretty sure that Strings
+    // are _not_ the right tool for the job here, lol
+    private String currentSelector;
+    private ArrayList<Pair<String, String>> currentRule;
+    private String currentProperty;
+    private String currentValue;
+    // important for quote escapes
+    private char previousChar;
+
+    private ParserState state;
+
+    /// Initialize all buffers to default values
+    public CssParser() {
+        result = new ArrayList<>();
+        currentSelector = "";
+        currentRule = new ArrayList<>();
+        currentProperty = "";
+        currentValue = "";
+        previousChar = '\0';
+
+        // We safely assume to start by reading a selector.
+        state = ParserState.SELECTORS;
+    }
+
     /**
-     * Parses a (valid) CSS file in a left-to-right, leftmost-derivation style.
+     * Parses a (valid) CSS file in a left-to-right, leftmost-derivation style. No additional lookup is needed,
+     * however we do keep a previousChar value for dealing with (annoying) escaped quotes.
      * It should be fast - I'd say something about time complexity if I knew anything about time complexity.
      * No guarantees are made about invalid CSS files. Also, no guarantees are made about valid CSS files, lol.
+     * <br>
+     * REQUIRES: A valid CSS file, as a raw String.
+     * MODIFIES: this
+     * EFFECTS: Returns a parsed CSS representation as several nested ArrayLists and Pairs of Strings.
      */
-    public static ArrayList<Pair<String, ArrayList<Pair<String, String>>>> parseLL(String input) {
-
-        // parser buffers
-        // essentially the CssTree type
-        var result = new ArrayList<Pair<String, ArrayList<Pair<String, String>>>>();
-        var currentSelector = "";
-        var currentRule = new ArrayList<Pair<String, String>>();
-        var currentProperty = "";
-        var currentValue = "";
-        var previousChar = '\0';
-
-        // We safely assume to start by reading a selector.
-        ParserState state = ParserState.SELECTORS;
+    public ArrayList<Pair<String, ArrayList<Pair<String, String>>>> parseCSS(String input) {
 
         for (char c : input.toCharArray()) {
             // System.out.print(state);
             // System.out.println(" " + c);
             switch (state) {
-                case SELECTORS:
-                    switch (c) {
-                        case '@':
-                            if (currentSelector.equals("")) {
-                                state = ParserState.MEDIA_SELECTORS;
-                            } else {
-                                currentSelector += c;
-                            }
-                            break;
-                        case '{':
-                            state = ParserState.ATTRIBUTE;
-                            break;
-                        case ' ': case '\n':
-                            break;
-                        // todo: do better than blindly create a string; pattern match on css selectors
-                        default:
-                            currentSelector += c;
-                            break;
-                    }
+                case SELECTORS: caseSelectors(c);
                     break;
-                case MEDIA_SELECTORS:
-                    switch (c) {
-                        // todo: don't entirely disregard media queries, also split between @media/@...
-                        case '{':
-                            state = ParserState.SELECTORS;
-                            // discard currentSelector
-                            currentSelector = "";
-                            break;
-                        default:
-                            currentSelector += c;
-                            break;
-                    }
+                case MEDIA_SELECTORS: caseMediaSelectors(c);
                     break;
-                case ATTRIBUTE:
-                    switch (c) {
-                        case ':':
-                            state = ParserState.VALUE;
-                            break;
-                        case '}':
-                            state = ParserState.SELECTORS;
-                            if (!currentValue.equals("") || !currentProperty.equals("")) {
-                                System.out.println("something's wrong");
-                                currentProperty = "";
-                                currentValue = "";
-                            }
-                            result.add(new Pair<>(currentSelector, currentRule));
-                            System.out.println(currentRule);
-                            currentSelector = "";
-                            currentRule = new ArrayList<>();
-                            break;
-                        case ' ': case '\n':
-                            break;
-                        default:
-                            currentProperty += c;
-                            break;
-                    }
+                case ATTRIBUTE: caseAttribute(c);
                     break;
-                case VALUE:
-                    switch (c) {
-                        case ';':
-                            state = ParserState.ATTRIBUTE;
-                            currentRule.add(new Pair<>(currentProperty, currentValue));
-                            currentProperty = "";
-                            currentValue = "";
-                            break;
-                        case '}':
-                            state = ParserState.SELECTORS;
-                            if (!currentValue.equals("") || !currentProperty.equals("")) {
-                                currentRule.add(new Pair<>(currentProperty, currentValue));
-                                currentProperty = "";
-                                currentValue = "";
-                            }
-                            result.add(new Pair<>(currentSelector, currentRule));
-                            currentSelector = "";
-                            currentRule = new ArrayList<>();
-                            break;
-                        case '\'':
-                            state = ParserState.SINGLE_QUOTES;
-                            currentValue += c;
-                            break;
-                        case '\"':
-                            state = ParserState.DOUBLE_QUOTES;
-                            currentValue += c;
-                            break;
-                        case ' ': case '\n':
-                            break;
-                        default:
-                            currentValue += c;
-                            break;
-                    }
+                case VALUE: caseValue(c);
                     break;
-                // quotes in css are exclusively? for paths: so we want to include the quotes themselves
-                case SINGLE_QUOTES:
-                    switch (c) {
-                        case '\'':
-                            if (previousChar != '\\') {
-                                state = ParserState.VALUE;
-                                currentValue += c;
-                                previousChar = '\0';
-                            } else {
-                                currentValue = currentValue.substring(0, currentValue.length() - 2);
-                                currentValue += c;
-                                previousChar = c;
-                            }
-                            break;
-                        default:
-                            currentValue += c;
-                            break;
-                    }
+                case SINGLE_QUOTES: caseSingleQuotes(c);
                     break;
-                case DOUBLE_QUOTES:
-                    switch (c) {
-                        case '\"':
-                            if (previousChar != '\\') {
-                                state = ParserState.VALUE;
-                                currentValue += c;
-                                previousChar = '\0';
-                            } else {
-                                currentValue = currentValue.substring(0, currentValue.length() - 2);
-                                currentValue += c;
-                                previousChar = c;
-                            }
-                            break;
-                        default:
-                            currentValue += c;
-                            break;
-                    }
+                case DOUBLE_QUOTES: caseDoubleQuotes(c);
                     break;
             }
         }
@@ -189,12 +86,179 @@ public class CssParser {
     }
 
     /**
-     * Takes an input string with units and returns out the value in pixels.
-     * This is a fault-tolerant system.
+     * EFFECTS: Handles and updates parser state/buffers for a single character while in the SELECTORS state.
+     * See also: the (slightly wrong) context-free grammar commented at the start of this file.
+     * MODIFIES: this
+     */
+    private void caseSelectors(char c) {
+        switch (c) {
+            case '@':
+                if (currentSelector.equals("")) {
+                    state = ParserState.MEDIA_SELECTORS;
+                } else {
+                    currentSelector += c;
+                }
+                break;
+            case '{':
+                state = ParserState.ATTRIBUTE;
+                break;
+            case ' ': case '\n':
+                break;
+            // todo: do better than blindly create a string; pattern match on css selectors
+            default:
+                currentSelector += c;
+                break;
+        }
+    }
+
+    /**
+     * EFFECTS: Handles and updates parser state/buffers for a single character while in the MEDIA_SELECTORS state.
+     * MODIFIES: this
+     */
+    private void caseMediaSelectors(char c) {
+        switch (c) {
+            // todo: don't entirely disregard media queries, also split between @media/@...
+            case '{':
+                state = ParserState.SELECTORS;
+                // discard currentSelector
+                currentSelector = "";
+                break;
+            default:
+                currentSelector += c;
+                break;
+        }
+    }
+
+    /**
+     * EFFECTS: Handles and updates parser state/buffers for a single character while in the ATTRIBUTE state.
+     * MODIFIES: this
+     */
+    private void caseAttribute(char c) {
+        switch (c) {
+            case ':':
+                state = ParserState.VALUE;
+                break;
+            case '}':
+                state = ParserState.SELECTORS;
+                if (!currentValue.equals("") || !currentProperty.equals("")) {
+                    // System.out.println("something's wrong");
+                    currentProperty = "";
+                    currentValue = "";
+                }
+                result.add(new Pair<>(currentSelector, currentRule));
+                currentSelector = "";
+                currentRule = new ArrayList<>();
+                break;
+            case ' ': case '\n':
+                break;
+            default:
+                currentProperty += c;
+                break;
+        }
+    }
+
+    /**
+     * EFFECTS: Handles and updates parser state/buffers for a single character while in the VALUE state.
+     * MODIFIES: this
+     */
+    private void caseValue(char c) {
+        switch (c) {
+            case ';':
+                state = ParserState.ATTRIBUTE;
+                updateCurrentRule();
+                break;
+            case '}':
+                state = ParserState.SELECTORS;
+                if (!currentValue.equals("") || !currentProperty.equals("")) {
+                    updateCurrentRule();
+                }
+                result.add(new Pair<>(currentSelector, currentRule));
+                currentSelector = "";
+                currentRule = new ArrayList<>();
+                break;
+            // todo: handle spaces better: they're actually important inside values
+            case ' ': case '\n': break; // believe me, i think this is ugly too but it passes checkstyle
+            case '\'':
+                state = ParserState.SINGLE_QUOTES;
+                currentValue += c;
+                break;
+            // intentional use of TERRIBLE SMOKING FOOTGUN behavior to check boxes
+            case '\"': state = ParserState.DOUBLE_QUOTES;
+            default: currentValue += c;
+                break;
+        }
+    }
+
+    /**
+     * Helper function to check method length boxes.
+     * EFFECTS: Adds a new property to the current rule.
+     * MODIFIES: this
+     */
+    private void updateCurrentRule() {
+        currentRule.add(new Pair<>(currentProperty, currentValue));
+        currentProperty = "";
+        currentValue = "";
+    }
+
+    // todo: handle additional escaped characters, though what we have right now isn't bad
+
+    /**
+     * EFFECTS: Handles and updates parser state/buffers for a single character while in the SINGLE_QUOTES state.
+     * MODIFIES: this
+     */
+    private void caseSingleQuotes(char c) {
+        switch (c) {
+            case '\'':
+                if (previousChar != '\\') {
+                    state = ParserState.VALUE;
+                    // quotes in css are exclusively? for paths: so we want to include the quotes themselves
+                    currentValue += c;
+                    previousChar = '\0';
+                } else {
+                    // possibly not the best way to handle this, may be better to keep the backslash
+                    currentValue = currentValue.substring(0, currentValue.length() - 2);
+                    currentValue += c;
+                    previousChar = c;
+                }
+                break;
+            default:
+                currentValue += c;
+                break;
+        }
+    }
+
+    /**
+     * EFFECTS: Handles and updates parser state/buffers for a single character while in the DOUBLE_QUOTES state.
+     * MODIFIES: this
+     */
+    private void caseDoubleQuotes(char c) {
+        switch (c) {
+            case '\"':
+                if (previousChar != '\\') {
+                    state = ParserState.VALUE;
+                    currentValue += c;
+                    previousChar = '\0';
+                } else {
+                    currentValue = currentValue.substring(0, currentValue.length() - 2);
+                    currentValue += c;
+                    previousChar = c;
+                }
+                break;
+            default:
+                currentValue += c;
+                break;
+        }
+    }
+
+    /**
+     * Takes an input string with units and returns out the value in pixels. This is a fault-tolerant system.
      * When given an invalid string (i.e. "12p53x"), it will produce an invalid result instead of throwing.
      * However, it should parse every valid string correctly.
+     * <br>
+     * REQUIRES: A string of the form [NUMBER][VALIDUNIT]
+     * EFFECTS: Returns a number, in pixels, that has been converted appropriately
      */
-    private double parseUnits(String input) {
+    private static double parseUnits(String input) {
         String numbers = "";
         String units = "";
         // imagine making a language without iterable strings, fml
@@ -210,9 +274,17 @@ public class CssParser {
         try {
             value = Float.parseFloat(numbers);
         } catch (NumberFormatException e) {
-            System.out.printf("Did not parse a float from %s, proceeding with value 0.0...%n", numbers);
+            // System.out.printf("Did not parse a float from %s, proceeding with value 0.0...%n", numbers);
             value = 0.0;
         }
+        return convertUnits(units, value);
+    }
+
+    /**
+     * REQUIRES: a String that is a unit, otherwise defaults to pixels
+     * EFFECTS: converts a value in some units to a value in pixels
+     */
+    private static double convertUnits(String units, double value) {
         // god case/break is such a fault-provoking design i hate it
         // good thing we avoid breaks entirely here lmao
         switch (units) {
@@ -226,7 +298,7 @@ public class CssParser {
             case "in": return value * 96;
             // not handled: % em ex ch rem lh rlh vw vh vmin vmax vb vi svw svh lvw lvh dvw dvh
             default:
-                System.out.printf("Unit %s not implemented, defaulting to %s in pixels...%n", units, value);
+                // System.out.printf("Unit %s not implemented, defaulting to %s in pixels...%n", units, value);
                 return value;
         }
     }