[Cloud] Add QuotedLinesParser helper parser (from TCC)

Signed-off-by: Irmo van den Berge <irmo.vandenberge@ziggo.nl>

src/main/java/com/bergerkiller/bukkit/common/cloud/parsers/QuotedLinesParser.java

@@ -0,0 +1,169 @@
+package com.bergerkiller.bukkit.common.cloud.parsers;
+
+import org.incendo.cloud.annotation.specifier.Greedy;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * Parses a String into separate lines separated by spaces. Lines with
+ * spaces can be parsed by surrounding them in quotes. Can be used to
+ * parse a {@link Greedy @Greedy} string further into lines while keeping support
+ * for quotes.
+ */
+public class QuotedLinesParser {
+    private final List<String> lines = new ArrayList<>();
+
+    /**
+     * Creates a new initially-empty QuotedLinesParser
+     *
+     * @return QuotedLinesParser
+     */
+    public static QuotedLinesParser create() {
+        return new QuotedLinesParser();
+    }
+
+    /**
+     * Gets whether lines were parsed at all, or that the input was all empty or whitespace
+     *
+     * @return True if lines were parsed
+     */
+    public boolean hasLines() {
+        return !lines.isEmpty();
+    }
+
+    /**
+     * Gets the lines of text parsed so far
+     *
+     * @return Lines
+     */
+    public List<String> getLines() {
+        return lines;
+    }
+
+    /**
+     * Gets the lines of text parsed so far as an array
+     *
+     * @return Lines
+     */
+    public String[] getLinesArray() {
+        return lines.toArray(new String[0]);
+    }
+
+    /**
+     * Adds a line to the results of this parser
+     *
+     * @param line Line to add
+     * @return this
+     */
+    public QuotedLinesParser addLine(String line) {
+        this.lines.add(line);
+        return this;
+    }
+
+    /**
+     * Adds lines to the results of this parser
+     *
+     * @param lines Lines to add
+     * @return this
+     */
+    public QuotedLinesParser addLines(String[] lines) {
+        this.lines.addAll(Arrays.asList(lines));
+        return this;
+    }
+
+    /**
+     * Adds lines to the results of this parser
+     *
+     * @param lines Lines to add
+     * @return this
+     */
+    public QuotedLinesParser addLines(Collection<String> lines) {
+        this.lines.addAll(lines);
+        return this;
+    }
+
+    /**
+     * Parses the lines from an input String
+     *
+     * @param input Input
+     * @return this
+     */
+    public QuotedLinesParser parse(String input) {
+        if (input != null) {
+            parse(input, 0, input.length());
+        }
+        return this;
+    }
+
+    /**
+     * Parses the lines from a substring of an input String
+     *
+     * @param input Input
+     * @param startIndex Start index offset into the input
+     * @param endIndex End index offset
+     * @return this
+     */
+    public QuotedLinesParser parse(String input, int startIndex, int endIndex) {
+        if (input != null) {
+            int currStartIndex = startIndex;
+            while ((currStartIndex = parseNext(input, currStartIndex, endIndex)) != -1);
+        }
+        return this;
+    }
+
+    private int parseNext(String input, int startIndex, int endIndex) {
+        // Omit preceding whitespace
+        while (startIndex < endIndex && input.charAt(startIndex) == ' ') {
+            startIndex++;
+        }
+
+        // Start with a quote? Quoted! Find the trailing quote.
+        if (startIndex < endIndex && input.charAt(startIndex) == '"') {
+            StringBuilder unescaped = null; // When we encounter a \, unescape
+            int partStartIndex = startIndex + 1;
+            int nextQuote;
+            while ((nextQuote = input.indexOf('"', partStartIndex)) != -1 && nextQuote < endIndex) {
+                if (input.charAt(nextQuote - 1) == '\\') {
+                    // Escaped quote found. Build up a string without the escaped chars.
+                    if (unescaped == null) {
+                        unescaped = new StringBuilder(input.length() - startIndex);
+                    }
+                    unescaped.append(input, partStartIndex, nextQuote);
+                    unescaped.append('"');
+                    partStartIndex = nextQuote + 1;
+                } else {
+                    // End of string part found!
+                    if (unescaped != null) {
+                        // Use builder
+                        unescaped.append(input, partStartIndex, nextQuote);
+                        addLine(unescaped.toString());
+                    } else {
+                        // Use substring
+                        addLine(input.substring(startIndex + 1, nextQuote));
+                    }
+
+                    // Continue next part past the quote
+                    return nextQuote + 1;
+                }
+            }
+
+            // Could not find a second quote. Parse as words and ignore it.
+        }
+
+        // Parse next word, instead
+        int space = input.indexOf(' ', startIndex);
+        if (space != -1) {
+            addLine(input.substring(startIndex, space));
+            return space + 1;
+        }
+
+        // End of string / final word. Only include if non-empty
+        if (startIndex < endIndex) {
+            addLine(input.substring(startIndex, endIndex));
+        }
+        return -1; // End
+    }
+}

src/test/java/com/bergerkiller/bukkit/common/StringUtilTest.java

@@ -6,6 +6,7 @@ import java.util.Arrays;
 import java.util.LinkedList;
 import java.util.List;
 
+import com.bergerkiller.bukkit.common.cloud.parsers.QuotedLinesParser;
 import org.bukkit.ChatColor;
 import org.junit.Ignore;
 import org.junit.Test;
@@ -17,6 +18,27 @@ import com.bergerkiller.bukkit.common.utils.StringUtil;
  */
 public class StringUtilTest {
 
+    @Test
+    public void testQuotedLinesParser() {
+        assertParsedQuotedLines("word", "word");
+        assertParsedQuotedLines("one two three", "one", "two", "three");
+        assertParsedQuotedLines("one  two  three", "one", "two", "three");
+        assertParsedQuotedLines("\"broken quote", "\"broken", "quote");
+        assertParsedQuotedLines("left \"escaped part\" right", "left", "escaped part", "right");
+        assertParsedQuotedLines("\"one two\" \"three four\"", "one two", "three four");
+        assertParsedQuotedLines("\"one  two\"  \"three  four\"", "one  two", "three  four");
+        assertParsedQuotedLines("\"\"", "");
+        assertParsedQuotedLines("");
+        assertParsedQuotedLines(" ");
+        assertParsedQuotedLines("\"", "\"");
+    }
+
+    private void assertParsedQuotedLines(String input, String... lines) {
+        QuotedLinesParser parser = new QuotedLinesParser();
+        parser.parse(input);
+        assertArrayEquals(lines, parser.getLinesArray());
+    }
+
     @Test
     public void testStringReplace() {
         assertEquals("ZBC", StringUtil.replace("ABC", 0, 1, "Z"));