add datalog parser for block

Author: KannarFr

src/main/java/org/biscuitsec/biscuit/token/builder/parser/Parser.java

@@ -1,7 +1,9 @@
 package org.biscuitsec.biscuit.token.builder.parser;
 
 import biscuit.format.schema.Schema;
+import io.vavr.collection.Stream;
 import org.biscuitsec.biscuit.crypto.PublicKey;
+import org.biscuitsec.biscuit.datalog.SymbolTable;
 import org.biscuitsec.biscuit.token.Policy;
 import io.vavr.Tuple2;
 import io.vavr.Tuple4;
@@ -10,12 +12,48 @@
 
 import java.time.OffsetDateTime;
 import java.time.format.DateTimeParseException;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.HashSet;
+import java.util.*;
 import java.util.function.Function;
 
 public class Parser {
+    /**
+     * Takes a datalog string with <code>\n</code> as datalog line separator. It tries to parse
+     * each line using fact, rule, check and scope sequentially.
+     *
+     * If one succeeds it returns Right(Block)
+     * else it returns a Map[lineNumber, List[Error]]
+     *
+     * @param index block index
+     * @param baseSymbols symbols table
+     * @param s datalog string to parse
+     * @return Either<Map<Integer, List<Error>>, Block>
+     */
+    public static Either<Map<Integer, List<Error>>, Block> datalog(long index, SymbolTable baseSymbols, String s) {
+        Block blockBuilder = new Block(index, baseSymbols);
+        Map<Integer, List<Error>> errors = new HashMap<>();
+
+        Stream.of(s.split("\n")).zipWithIndex().forEach(indexedLine -> {
+            Integer lineNumber = indexedLine._2;
+            String codeLine = indexedLine._1;
+            List<Error> lineErrors = new ArrayList<>();
+
+            fact(codeLine).bimap(lineErrors::add, r -> r._2).map(blockBuilder::add_fact);
+            rule(codeLine).bimap(lineErrors::add, r -> r._2).map(blockBuilder::add_rule);
+            check(codeLine).bimap(lineErrors::add, r -> r._2).map(blockBuilder::add_check);
+            scope(codeLine).bimap(lineErrors::add, r -> r._2).map(blockBuilder::add_scope);
+
+            if (lineErrors.size() > 3) {
+                errors.put(lineNumber, lineErrors);
+            }
+        });
+
+        if (!errors.isEmpty()) {
+            return Either.left(errors);
+        }
+
+        return Either.right(blockBuilder);
+    }
+
     public static Either<Error, Tuple2<String, Fact>> fact(String s) {
         Either<Error, Tuple2<String, Predicate>> res = fact_predicate(s);
         if (res.isLeft()) {

src/test/java/org/biscuitsec/biscuit/builder/parser/ParserTest.java

@@ -5,6 +5,7 @@
 import org.biscuitsec.biscuit.datalog.SymbolTable;
 import org.biscuitsec.biscuit.datalog.TemporarySymbolTable;
 import org.biscuitsec.biscuit.datalog.expressions.Op;
+import org.biscuitsec.biscuit.token.Biscuit;
 import org.biscuitsec.biscuit.token.builder.parser.Error;
 import org.biscuitsec.biscuit.token.builder.parser.Parser;
 import io.vavr.Tuple2;
@@ -15,7 +16,7 @@
 import org.junit.jupiter.api.Test;
 
 import static org.biscuitsec.biscuit.datalog.Check.Kind.One;
-import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.*;
 
 import java.util.*;
 
@@ -360,4 +361,40 @@ void testParens() throws org.biscuitsec.biscuit.error.Error.Execution {
         assertEquals(new org.biscuitsec.biscuit.datalog.Term.Integer(9), value2);
         assertEquals("(1 + 2) * 3", ex2.print(s2).get());
     }
+
+    @Test
+    void testDatalogSucceeds() throws org.biscuitsec.biscuit.error.Error.Parser {
+        SymbolTable symbols = Biscuit.default_symbol_table();
+
+        String l1 = "fact1(1)";
+        String l2 = "fact2(\"2\")";
+        String l3 = "rule1(2) <- fact2(\"2\")";
+        String l4 = "check if rule1(2)";
+        String toParse = String.join("\n", Arrays.asList(l1, l2, l3, l4));
+
+        Either<Map<Integer, List<Error>>, Block> output = Parser.datalog(1, symbols, toParse);
+        assertTrue(output.isRight());
+
+        Block validBlock = new Block(1, symbols);
+        validBlock.add_fact(l1);
+        validBlock.add_fact(l2);
+        validBlock.add_rule(l3);
+        validBlock.add_check(l4);
+
+        output.forEach(block ->
+            assertArrayEquals(block.build().to_bytes().get(), validBlock.build().to_bytes().get())
+        );
+    }
+
+    @Test
+    void testDatalogFailed() {
+        SymbolTable symbols = Biscuit.default_symbol_table();
+
+        String l1 = "fact(1)";
+        String l2 = "check fact(1)"; // typo missing "if"
+        String toParse = String.join("\n", Arrays.asList(l1, l2));
+
+        Either<Map<Integer, List<Error>>, Block> output = Parser.datalog(1, symbols, toParse);
+        assertTrue(output.isLeft());
+    }
 }