Use format specifiers when formatting null pointers & strings

format.cc

@@ -425,12 +425,17 @@ class BasicArgFormatter : public ArgVisitor<Impl, void> {
   BasicWriter<Char> &writer() { return writer_; }
   FormatSpec &spec() { return spec_; }
   
-  void write_bool(bool value) {
+  void write(bool value) {
     const char *str_value = value ? "true" : "false";
     Arg::StringValue<char> str = { str_value, strlen(str_value) };
     writer_.write_str(str, spec_);
   }
 
+  void write(const char *value) {
+    Arg::StringValue<char> str = {value, 0};
+    writer_.write_str(str, spec_);
+  }
+
  public:
   BasicArgFormatter(BasicWriter<Char> &w, FormatSpec &s)
   : writer_(w), spec_(s) {}
@@ -444,7 +449,7 @@ class BasicArgFormatter : public ArgVisitor<Impl, void> {
   void visit_bool(bool value) {
     if (spec_.type_)
       return visit_any_int(value);
-    write_bool(value);
+    write(value);
   }
 
   void visit_char(int value) {
@@ -479,8 +484,7 @@ class BasicArgFormatter : public ArgVisitor<Impl, void> {
   void visit_cstring(const char *value) {
     if (spec_.type_ == 'p')
       return write_pointer(value);
-    Arg::StringValue<char> str = {value, 0};
-    writer_.write_str(str, spec_);
+    write(value);
   }
 
   void visit_string(Arg::StringValue<char> value) {
@@ -522,9 +526,12 @@ class PrintfArgFormatter :
     public BasicArgFormatter<PrintfArgFormatter<Char>, Char> {
 
   void write_null_pointer() {
-    this->writer() << "(nil)";
+    this->spec().type_ = 0;
+    this->write("(nil)");
   }
 
+  typedef BasicArgFormatter<PrintfArgFormatter<Char>, Char> Base;
+
  public:
   PrintfArgFormatter(BasicWriter<Char> &w, FormatSpec &s)
   : BasicArgFormatter<PrintfArgFormatter<Char>, Char>(w, s) {}
@@ -534,7 +541,7 @@ class PrintfArgFormatter :
     if (fmt_spec.type_ != 's')
       return this->visit_any_int(value);
     fmt_spec.type_ = 0;
-    this->write_bool(value);
+    this->write(value);
   }
 
   void visit_char(int value) {
@@ -561,18 +568,18 @@ class PrintfArgFormatter :
 
   void visit_cstring(const char *value) {
     if (value)
-      BasicArgFormatter<PrintfArgFormatter<Char>, Char>::visit_cstring(value);
+      Base::visit_cstring(value);
     else if (this->spec().type_ == 'p')
       write_null_pointer();
     else
-      this->writer() << "(null)";
+      this->write("(null)");
   }
 
   void visit_pointer(const void *value) {
     if (value)
-      BasicArgFormatter<PrintfArgFormatter<Char>, Char>::visit_pointer(value);
-    else
-      write_null_pointer();
+      return Base::visit_pointer(value);
+    this->spec().type_ = 0;
+    write_null_pointer();
   }
 
   void visit_custom(Arg::CustomValue c) {

test/printf-test.cc

@@ -425,6 +425,7 @@ TEST(PrintfTest, String) {
   EXPECT_PRINTF("abc", "%s", "abc");
   const char *null_str = 0;
   EXPECT_PRINTF("(null)", "%s", null_str);
+  EXPECT_PRINTF("    (null)", "%10s", null_str);
   // TODO: wide string
 }
 
@@ -434,6 +435,7 @@ TEST(PrintfTest, Pointer) {
   EXPECT_PRINTF(fmt::format("{}", p), "%p", p);
   p = 0;
   EXPECT_PRINTF("(nil)", "%p", p);
+  EXPECT_PRINTF("     (nil)", "%10p", p);
   const char *s = "test";
   EXPECT_PRINTF(fmt::format("{:p}", s), "%p", s);
   const char *null_str = 0;