Add function FILE_WRITE with unit test

h2/src/docsrc/help/help.csv

@@ -3821,6 +3821,16 @@ SELECT LENGTH(FILE_READ('~/.h2.server.properties')) LEN;
 SELECT FILE_READ('http://localhost:8182/stylesheet.css', NULL) CSS;
 "
 
+"Functions (System)","FILE_WRITE","
+FILE_WRITE(Blob , fileNameString)
+","
+Write the supplied parameter into a file. Return the number of bytes written.
+
+Write access to folder, and admin rights are required to execute this command.
+","
+SELECT FILE_WRITE('Hello world', '/tmp/hello.txt')) LEN;
+"
+
 "Functions (System)","GREATEST","
 GREATEST(aValue, bValue [,...])
 ","

h2/src/main/org/h2/expression/Function.java

@@ -7,6 +7,7 @@ package org.h2.expression;
 
 import static org.h2.util.ToChar.toChar;
 
+import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
@@ -47,6 +48,7 @@ import org.h2.tools.CompressTool;
 import org.h2.tools.Csv;
 import org.h2.util.AutoCloseInputStream;
 import org.h2.util.DateTimeUtils;
+import org.h2.util.IOUtils;
 import org.h2.util.JdbcUtils;
 import org.h2.util.MathUtils;
 import org.h2.util.New;
@@ -116,7 +118,7 @@ public class Function extends Expression implements FunctionCall {
             ARRAY_LENGTH = 217, LINK_SCHEMA = 218, GREATEST = 219, LEAST = 220,
             CANCEL_SESSION = 221, SET = 222, TABLE = 223, TABLE_DISTINCT = 224,
             FILE_READ = 225, TRANSACTION_ID = 226, TRUNCATE_VALUE = 227,
-            NVL2 = 228, DECODE = 229, ARRAY_CONTAINS = 230;
+            NVL2 = 228, DECODE = 229, ARRAY_CONTAINS = 230, FILE_WRITE = 232;
 
     /**
      * Used in MySQL-style INSERT ... ON DUPLICATE KEY UPDATE ... VALUES
@@ -453,6 +455,8 @@ public class Function extends Expression implements FunctionCall {
                 2, Value.NULL, false, false, true);
         addFunction("FILE_READ", FILE_READ,
                 VAR_ARGS, Value.NULL, false, false, true);
+        addFunction("FILE_WRITE", FILE_WRITE,
+                2, Value.LONG, false, false, true);
         addFunctionNotDeterministic("TRANSACTION_ID", TRANSACTION_ID,
                 0, Value.STRING);
         addFunctionWithNull("DECODE", DECODE,
@@ -1597,6 +1601,24 @@ public class Function extends Expression implements FunctionCall {
             }
             break;
         }
+        case FILE_WRITE: {
+            session.getUser().checkAdmin();
+            result = ValueNull.INSTANCE;
+            String fileName = v1.getString();
+            try {
+                FileOutputStream fileOutputStream = new FileOutputStream(fileName);
+                InputStream in = v0.getInputStream();
+                try {
+                    result = ValueLong.get(IOUtils.copyAndClose(in,
+                            fileOutputStream));
+                } finally {
+                    in.close();
+                }
+            } catch (IOException e) {
+                throw DbException.convertIOException(e, fileName);
+            }
+            break;
+        }
         case TRUNCATE_VALUE: {
             result = v0.convertPrecision(v1.getLong(), v2.getBoolean());
             break;

h2/src/test/org/h2/test/db/TestFunctions.java

@@ -6,6 +6,9 @@
 package org.h2.test.db;
 
 import java.io.BufferedInputStream;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.OutputStream;
@@ -43,6 +46,7 @@ import org.h2.test.TestBase;
 import org.h2.tools.SimpleResultSet;
 import org.h2.util.IOUtils;
 import org.h2.util.New;
+import org.h2.util.StringUtils;
 import org.h2.value.Value;
 
 /**
@@ -96,6 +100,7 @@ public class TestFunctions extends TestBase implements AggregateFunction {
         testToCharFromText();
         testTranslate();
         testGenerateSeries();
+        testFileWrite();
 
         deleteDb("functions");
     }
@@ -622,6 +627,36 @@ public class TestFunctions extends TestBase implements AggregateFunction {
         FileUtils.delete(fileName);
     }
 
+
+    private void testFileWrite() throws Exception {
+        Connection conn = getConnection("functions");
+        Statement stat = conn.createStatement();
+        // Copy data into clob table
+        stat.execute("DROP TABLE TEST IF EXISTS");
+        PreparedStatement pst = conn.prepareStatement(
+                "CREATE TABLE TEST(data clob) AS SELECT ? " + "data");
+        Properties prop = System.getProperties();
+        ByteArrayOutputStream os = new ByteArrayOutputStream(prop.size());
+        prop.store(os, "");
+        pst.setBinaryStream(1, new ByteArrayInputStream(os.toByteArray()));
+        pst.execute();
+        os.close();
+        String fileName = new File(getBaseDir(), "test.txt").getPath();
+        FileUtils.delete(fileName);
+        ResultSet rs = stat.executeQuery("SELECT FILE_WRITE(data, " +
+                StringUtils.quoteStringSQL(fileName) + ") len from test");
+        assertTrue(rs.next());
+        assertEquals(os.size(), rs.getInt(1));
+        InputStreamReader r = new InputStreamReader(FileUtils.newInputStream(fileName));
+        // Compare expected content with written file content
+        String ps2 = IOUtils.readStringAndClose(r, -1);
+        assertEquals(os.toString(), ps2);
+        conn.close();
+        FileUtils.delete(fileName);
+    }
+
+
+
     /**
      * This median implementation keeps all objects in memory.
      */