Move logic to write to stdout into CodeWriter

This will allow us to reuse it when we write C++ code.
I think this will mostly come in handy for debugging.

While here, rename the helper functions in accordance with the style
guide.

Test: unittests
Bug: 24220933

Change-Id: I269eb4a0dda10588c2ae77b7c8f2b00e50e70047

5 files changed, 37 insertions, 27 deletions

diff --git a/ast_cpp_unittest.cpp b/ast_cpp_unittest.cpp
index ce1981d..0b2d707 100644
--- a/ast_cpp_unittest.cpp
+++ b/ast_cpp_unittest.cpp
@@ -79,7 +79,7 @@ TEST(AstCppTests, GeneratesHeader) {
     }}
   };
   string actual_output;
-  CodeWriterPtr writer = get_string_writer(&actual_output);
+  CodeWriterPtr writer = GetStringWriter(&actual_output);
   cpp_header.Write(writer.get());
   EXPECT_EQ(string(kExpectedHeaderOutput), actual_output);
 }
diff --git a/ast_java_unittest.cpp b/ast_java_unittest.cpp
index 2d90462..31dfb5a 100644
--- a/ast_java_unittest.cpp
+++ b/ast_java_unittest.cpp
@@ -46,7 +46,7 @@ TEST(AstJavaTests, GeneratesClass) {
   a_class.extends = &extend_type;
 
   string actual_output;
-  CodeWriterPtr writer = get_string_writer(&actual_output);
+  CodeWriterPtr writer = GetStringWriter(&actual_output);
   a_class.Write(writer.get());
   EXPECT_EQ(string(kExpectedClassOutput), actual_output);
 }
diff --git a/code_writer.cpp b/code_writer.cpp
index e2ef362..7425c39 100644
--- a/code_writer.cpp
+++ b/code_writer.cpp
@@ -16,10 +16,14 @@
 
 #include "code_writer.h"
 
+#include <iostream>
 #include <stdarg.h>
 
 #include <base/stringprintf.h>
 
+using std::cerr;
+using std::endl;
+
 namespace android {
 namespace aidl {
 
@@ -43,9 +47,13 @@ class StringCodeWriter : public CodeWriter {
 
 class FileCodeWriter : public CodeWriter {
  public:
-  FileCodeWriter(FILE* output_file) : output_(output_file) {}
+  FileCodeWriter(FILE* output_file, bool close_on_destruction)
+      : output_(output_file),
+        close_on_destruction_(close_on_destruction) {}
   ~FileCodeWriter() {
-    fclose(output_);
+    if (close_on_destruction_) {
+      fclose(output_);
+    }
   }
 
   bool Write(const char* format, ...) override {
@@ -59,15 +67,34 @@ class FileCodeWriter : public CodeWriter {
 
  private:
   FILE* output_;
+  bool close_on_destruction_;
 };  // class StringCodeWriter
 
 }  // namespace
 
-CodeWriterPtr get_file_writer(FILE* output_file) {
-  return CodeWriterPtr(new FileCodeWriter(output_file));
+CodeWriterPtr GetFileWriter(const std::string& output_file) {
+  CodeWriterPtr result;
+  FILE* to = nullptr;
+  bool close_on_destruction = true;
+  if (output_file == "-") {
+    to = stdout;
+    close_on_destruction = false;
+  } else {
+    // open file in binary mode to ensure that the tool produces the
+    // same output on all platforms !!
+    to = fopen(output_file.c_str(), "wb");
+  }
+
+  if (to != nullptr) {
+    result.reset(new FileCodeWriter(to, close_on_destruction));
+  } else {
+    cerr << "unable to open " << output_file << " for write" << endl;
+  }
+
+  return result;
 }
 
-CodeWriterPtr get_string_writer(std::string* output_buffer) {
+CodeWriterPtr GetStringWriter(std::string* output_buffer) {
   return CodeWriterPtr(new StringCodeWriter(output_buffer));
 }
 
diff --git a/code_writer.h b/code_writer.h
index bc617c0..0519d74 100644
--- a/code_writer.h
+++ b/code_writer.h
@@ -38,14 +38,12 @@ class CodeWriter {
 using CodeWriterPtr = std::unique_ptr<CodeWriter>;
 
 // Get a CodeWriter that writes to |output_file|.
-// The CodeWriter will take ownership of |output_file| and close it
-// upon destruction.
-CodeWriterPtr get_file_writer(FILE* output_file);
+CodeWriterPtr GetFileWriter(const std::string& output_file);
 
 // Get a CodeWriter that writes to a string buffer.
 // Caller retains ownership of the buffer.
 // The buffer must outlive the CodeWriter.
-CodeWriterPtr get_string_writer(std::string* output_buffer);
+CodeWriterPtr GetStringWriter(std::string* output_buffer);
 
 }  // namespace aidl
 }  // namespace android
diff --git a/generate_java.cpp b/generate_java.cpp
index 5626d3d..868783c 100644
--- a/generate_java.cpp
+++ b/generate_java.cpp
@@ -78,22 +78,7 @@ generate_java(const string& filename, const string& originalSrc,
         document->originalSrc = originalSrc;
         document->classes.push_back(cl);
 
-//    printf("outputting... filename=%s\n", filename.c_str());
-    FILE* to;
-    if (filename == "-") {
-        to = stdout;
-    } else {
-       /* open file in binary mode to ensure that the tool produces the
-        * same output on all platforms !!
-        */
-        to = fopen(filename.c_str(), "wb");
-        if (to == NULL) {
-            fprintf(stderr, "unable to open %s for write\n", filename.c_str());
-            return 1;
-        }
-    }
-
-    CodeWriterPtr code_writer = get_file_writer(to);
+    CodeWriterPtr code_writer = GetFileWriter(filename);
     document->Write(code_writer.get());
 
     return 0;