Do not write to code file if header is missing

3 files changed, 86 insertions, 49 deletions

diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/CodeWriterTests.java b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/CodeWriterTests.java
index b0ff40c..2b3ad6d 100644
--- a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/CodeWriterTests.java
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/CodeWriterTests.java
@@ -14,17 +14,21 @@ public class CodeWriterTests {
     @Test
     public void whenFileDoesNotExistThenCustomAreasAreEmpty() throws IOException {
         var stringWriter = new StringWriter();
-        var codeWriter = CodeWriter.file(
-            new CodeWriter.InMemoryCodeWriterFile(Optional.empty(), stringWriter),
-            "//"
+        var file = new CodeWriter.InMemoryCodeWriterFile(Optional.empty(), stringWriter);
+
+        CodeWriter.writeTo(
+            file,
+            "//",
+            codeWriter -> {
+                codeWriter.writeHeader();
+                codeWriter.write("Before");
+                codeWriter.newLine();
+                codeWriter.writeCustomArea("body");
+                codeWriter.write("After");
+                codeWriter.newLine();
+            }
         );
 
-        codeWriter.writeHeader();
-        codeWriter.write("Before");
-        codeWriter.newLine();
-        codeWriter.writeCustomArea("body");
-        codeWriter.write("After");
-        codeWriter.newLine();
 
         assertThat(stringWriter.toString(), equalTo("""
             // Generated by hobgoblin.
@@ -39,21 +43,28 @@ public class CodeWriterTests {
     @Test
     public void whenExistingFileIsMissingCustomAreaThenCustomAreaIsEmpty() throws IOException {
         var stringWriter = new StringWriter();
-        var codeWriter = CodeWriter.file(
-            new CodeWriter.InMemoryCodeWriterFile(Optional.of(""), stringWriter),
-            "//"
-        );
+        var originalContents = """
+            // Generated by hobgoblin.
 
-        codeWriter.writeHeader();
-        codeWriter.write("Before");
-        codeWriter.newLine();
-        codeWriter.writeCustomArea("body");
-        codeWriter.write("After");
-        codeWriter.newLine();
+            """;
+        var file = new CodeWriter.InMemoryCodeWriterFile(Optional.of(originalContents), stringWriter);
+
+        CodeWriter.writeTo(
+            file,
+            "//",
+            codeWriter -> {
+                codeWriter.writeHeader();
+                codeWriter.write("Before");
+                codeWriter.newLine();
+                codeWriter.writeCustomArea("body");
+                codeWriter.write("After");
+                codeWriter.newLine();
+            }
+        );
 
         assertThat(stringWriter.toString(), equalTo("""
             // Generated by hobgoblin.
-            
+
             Before
             // Custom area start: body
             // Custom area end: body
@@ -65,6 +76,8 @@ public class CodeWriterTests {
     public void whenExistingFileHasCustomAreasThenCustomAreaContentsArePreserved() throws IOException {
         var stringWriter = new StringWriter();
         var originalContents = """
+            // Generated by hobgoblin.
+
             // Custom area start: head
             Custom head.
             // Custom area end: head
@@ -72,18 +85,21 @@ public class CodeWriterTests {
             Custom body.
             // Custom area end: body
             """;
-        var codeWriter = CodeWriter.file(
-            new CodeWriter.InMemoryCodeWriterFile(Optional.of(originalContents), stringWriter),
-            "//"
-        );
+        var file = new CodeWriter.InMemoryCodeWriterFile(Optional.of(originalContents), stringWriter);
 
-        codeWriter.writeHeader();
-        codeWriter.writeCustomArea("head");
-        codeWriter.writeCustomArea("body");
+        CodeWriter.writeTo(
+            file,
+            "//",
+            codeWriter -> {
+                codeWriter.writeHeader();
+                codeWriter.writeCustomArea("head");
+                codeWriter.writeCustomArea("body");
+            }
+        );
 
         assertThat(stringWriter.toString(), equalTo("""
             // Generated by hobgoblin.
-            
+
             // Custom area start: head
             Custom head.
             // Custom area end: head
@@ -92,4 +108,31 @@ public class CodeWriterTests {
             // Custom area end: body
             """));
     }
+
+    @Test
+    public void whenExistingFileIsMissingHeaderThenNothingIsWritten() throws IOException {
+        var stringWriter = new StringWriter();
+        var originalContents = """
+            // Custom area start: head
+            Custom head.
+            // Custom area end: head
+            // Custom area start: body
+            Custom body.
+            // Custom area end: body
+            """;
+        var file = new CodeWriter.InMemoryCodeWriterFile(Optional.of(originalContents), stringWriter);
+
+        CodeWriter.writeTo(
+            file,
+            "//",
+            codeWriter -> {
+                codeWriter.writeHeader();
+                codeWriter.writeCustomArea("head");
+                codeWriter.writeCustomArea("body");
+            }
+        );
+
+        assertThat(stringWriter.toString(), equalTo(""));
+        assertThat(file.isWriterOpened(), equalTo(false));
+    }
 }
diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriterTests.java b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriterTests.java
index 2889032..9b16328 100644
--- a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriterTests.java
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriterTests.java
@@ -1698,7 +1698,9 @@ public class JavaWriterTests {
         var string = write(
             writer -> writer.writeTypeDeclaration(java),
             """
-                public class Point {
+            // Generated by hobgoblin.
+
+            public class Point {
                 // Custom area start: Point body
                 // <custom area>
                 // Custom area end: Point body
@@ -1717,24 +1719,20 @@ public class JavaWriterTests {
 
     // == Doc comments ==
 
-    private String write(Write write) throws IOException {
+    private String write(JavaWriter.Write write) throws IOException {
         return write(write, Optional.empty());
     }
 
-    private String write(Write write, String originalContents) throws IOException {
+    private String write(JavaWriter.Write write, String originalContents) throws IOException {
         return write(write, Optional.of(originalContents));
     }
 
-    private String write(Write write, Optional<String> originalContents) throws IOException {
+    private String write(JavaWriter.Write write, Optional<String> originalContents) throws IOException {
         var stringWriter = new StringWriter();
-        var javaWriter = JavaWriter.file(
-            new CodeWriter.InMemoryCodeWriterFile(originalContents, stringWriter)
+        JavaWriter.writeTo(
+            new CodeWriter.InMemoryCodeWriterFile(originalContents, stringWriter),
+            write
         );
-        write.write(javaWriter);
         return stringWriter.toString();
     }
-
-    private interface Write {
-        void write(JavaWriter writer) throws IOException;
-    }
 }
diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriterTests.java b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriterTests.java
index e9edb72..4a81031 100644
--- a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriterTests.java
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriterTests.java
@@ -1204,24 +1204,20 @@ public class RustWriterTests {
         assertThat(string, equalTo("r#const"));
     }
 
-    private String write(Write write) throws IOException {
+    private String write(RustWriter.Write write) throws IOException {
         return write(write, Optional.empty());
     }
 
-    private String write(Write write, String originalContents) throws IOException {
+    private String write(RustWriter.Write write, String originalContents) throws IOException {
         return write(write, Optional.of(originalContents));
     }
 
-    private String write(Write write, Optional<String> originalContents) throws IOException {
+    private String write(RustWriter.Write write, Optional<String> originalContents) throws IOException {
         var stringWriter = new StringWriter();
-        var rustWriter = RustWriter.file(
-            new CodeWriter.InMemoryCodeWriterFile(originalContents, stringWriter)
+        RustWriter.writeTo(
+            new CodeWriter.InMemoryCodeWriterFile(originalContents, stringWriter),
+            write
         );
-        write.write(rustWriter);
         return stringWriter.toString();
     }
-
-    private interface Write {
-        void write(RustWriter writer) throws IOException;
-    }
 }