Escape "--" in markdown rendering for GN reference docs.

tools/gn/standard_out.cc

Index: tools/gn/standard_out.cc
diff --git a/tools/gn/standard_out.cc b/tools/gn/standard_out.cc
index 6d3960e6f4863b418cc333c92fbeb527c9a5511d..696050e3933e017e2b4316953d59d0c177e6344c 100644
--- a/tools/gn/standard_out.cc
+++ b/tools/gn/standard_out.cc
@@ -8,7 +8,9 @@
 
 #include "base/command_line.h"
 #include "base/logging.h"
+#include "base/strings/string_piece.h"
 #include "base/strings/string_split.h"
+#include "base/strings/string_util.h"
 #include "build/build_config.h"
 #include "tools/gn/switches.h"
 
@@ -124,8 +126,22 @@ void OutputString(const std::string& output, TextDecoration dec) {
     }
   }
 
-  ::WriteFile(hstdout, output.c_str(), static_cast<DWORD>(output.size()),
-              &written, nullptr);
+  // https://code.google.com/p/gitiles/issues/detail?id=77
+  // Gitiles will replace "--" with an em dash in non-code text.
+  // Figuring out all instances of this might be difficult, but
+  // we can at least escape the instances where this shows up in
+  // a heading.
+  if (is_markdown && dec==DECORATION_YELLOW) {

[brettw, 2015/09/04 18:04:29]

Need spaces around ==

+    std::string tmpstr = output;

[brettw, 2015/09/04 18:04:30]

Why not just do
  if (...) {
    base::ReplaceSubstringsAfterOffset(&output, ...);
  }
  ::WriteFile(...);

[Dirk Pranke, 2015/09/05 01:53:42]

output is a const, so we can't modify it. 

I've uploaded a version that always makes the copy; I doubt the performance
matters in this case.

+    base::ReplaceSubstringsAfterOffset(&tmpstr, 0,
+                                       StringPiece("--"),
+                                       StringPiece("\\--"));

[Dirk Pranke, 2015/09/03 01:04:45]

Is this the best/easiest way to do a "replace all" in a string?

[brettw, 2015/09/04 18:04:29]

Sure, but you can remove the explicit StringPiece constructors and just type
"--"

+    ::WriteFile(hstdout, tmpstr.c_str(), static_cast<DWORD>(tmpstr.size()),
+                &written, nullptr);
+  } else {
+    ::WriteFile(hstdout, output.c_str(), static_cast<DWORD>(output.size()),
+                &written, nullptr);
+  }
 
   if (is_markdown) {
     OutputMarkdownDec(dec);
@@ -162,7 +178,21 @@ void OutputString(const std::string& output, TextDecoration dec) {
     }
   }
 
-  WriteToStdOut(output.data());
+  if (is_markdown && dec==DECORATION_YELLOW) {

[brettw, 2015/09/04 18:04:29]

Ditto

+    std::string tmpstr = output;

[brettw, 2015/09/04 18:04:29]

Ditto

+
+    // https://code.google.com/p/gitiles/issues/detail?id=77
+    // Gitiles will replace "--" with an em dash in non-code text.
+    // Figuring out all instances of this might be difficult, but
+    // we can at least escape the instances where this shows up in
+    // a heading.
+    base::ReplaceSubstringsAfterOffset(&tmpstr, 0,
+                                       base::StringPiece("--"),
+                                       base::StringPiece("\\--"));
+    WriteToStdOut(tmpstr.data());
+  } else {
+    WriteToStdOut(output.data());
+  }
 
   if (is_markdown) {
     OutputMarkdownDec(dec);