From cfb4ad2f2383d20f6446d8c63a3e992edbb8b8b8 Mon Sep 17 00:00:00 2001
From: Oliver Middleton <olliemail27@gmail.com>
Date: Thu, 2 Jun 2016 16:16:21 +0100
Subject: [PATCH] rustdoc: Don't generate empty files for stripped items

We need to traverse stripped modules to generate redirect pages, but we shouldn't generate
anything else for them.

This now renders the file contents to a Vec before writing it to a file in one go. I think
that's probably a better strategy anyway.
---
 src/librustdoc/html/render.rs   | 41 +++++++++++++++++++--------------
 src/test/rustdoc/issue-34025.rs | 22 ++++++++++++++++++
 2 files changed, 46 insertions(+), 17 deletions(-)
 create mode 100644 src/test/rustdoc/issue-34025.rs

diff --git a/src/librustdoc/html/render.rs b/src/librustdoc/html/render.rs
index 396f71173f834..bc721a67b1c4a 100644
--- a/src/librustdoc/html/render.rs
+++ b/src/librustdoc/html/render.rs
@@ -1255,7 +1255,6 @@ impl Context {
 
         info!("Recursing into {}", self.dst.display());
 
-        mkdir(&self.dst).unwrap();
         let ret = f(self);
 
         info!("Recursed; leaving {}", self.dst.display());
@@ -1299,7 +1298,7 @@ impl Context {
     fn item<F>(&mut self, item: clean::Item, mut f: F) -> Result<(), Error> where
         F: FnMut(&mut Context, clean::Item),
     {
-        fn render(w: File, cx: &Context, it: &clean::Item,
+        fn render(writer: &mut io::Write, cx: &Context, it: &clean::Item,
                   pushname: bool) -> io::Result<()> {
             // A little unfortunate that this is done like this, but it sure
             // does make formatting *a lot* nicer.
@@ -1334,12 +1333,8 @@ impl Context {
 
             reset_ids(true);
 
-            // We have a huge number of calls to write, so try to alleviate some
-            // of the pain by using a buffered writer instead of invoking the
-            // write syscall all the time.
-            let mut writer = BufWriter::new(w);
             if !cx.render_redirect_pages {
-                layout::render(&mut writer, &cx.shared.layout, &page,
+                layout::render(writer, &cx.shared.layout, &page,
                                &Sidebar{ cx: cx, item: it },
                                &Item{ cx: cx, item: it },
                                cx.shared.css_file_extension.is_some())?;
@@ -1352,10 +1347,10 @@ impl Context {
                         url.push_str("/");
                     }
                     url.push_str(&item_path(it));
-                    layout::redirect(&mut writer, &url)?;
+                    layout::redirect(writer, &url)?;
                 }
             }
-            writer.flush()
+            Ok(())
         }
 
         // Stripped modules survive the rustdoc passes (i.e. `strip-private`)
@@ -1376,9 +1371,16 @@ impl Context {
             let mut item = Some(item);
             self.recurse(name, |this| {
                 let item = item.take().unwrap();
-                let joint_dst = this.dst.join("index.html");
-                let dst = try_err!(File::create(&joint_dst), &joint_dst);
-                try_err!(render(dst, this, &item, false), &joint_dst);
+
+                let mut buf = Vec::new();
+                render(&mut buf, this, &item, false).unwrap();
+                // buf will be empty if the module is stripped and there is no redirect for it
+                if !buf.is_empty() {
+                    let joint_dst = this.dst.join("index.html");
+                    try_err!(fs::create_dir_all(&this.dst), &this.dst);
+                    let mut dst = try_err!(File::create(&joint_dst), &joint_dst);
+                    try_err!(dst.write_all(&buf), &joint_dst);
+                }
 
                 let m = match item.inner {
                     clean::StrippedItem(box clean::ModuleItem(m)) |
@@ -1387,7 +1389,7 @@ impl Context {
                 };
 
                 // render sidebar-items.js used throughout this module
-                {
+                if !this.render_redirect_pages {
                     let items = this.build_sidebar_items(&m);
                     let js_dst = this.dst.join("sidebar-items.js");
                     let mut js_out = BufWriter::new(try_err!(File::create(&js_dst), &js_dst));
@@ -1401,10 +1403,15 @@ impl Context {
                 Ok(())
             })
         } else if item.name.is_some() {
-            let joint_dst = self.dst.join(&item_path(&item));
-
-            let dst = try_err!(File::create(&joint_dst), &joint_dst);
-            try_err!(render(dst, self, &item, true), &joint_dst);
+            let mut buf = Vec::new();
+            render(&mut buf, self, &item, true).unwrap();
+            // buf will be empty if the item is stripped and there is no redirect for it
+            if !buf.is_empty() {
+                let joint_dst = self.dst.join(&item_path(&item));
+                try_err!(fs::create_dir_all(&self.dst), &self.dst);
+                let mut dst = try_err!(File::create(&joint_dst), &joint_dst);
+                try_err!(dst.write_all(&buf), &joint_dst);
+            }
             Ok(())
         } else {
             Ok(())
diff --git a/src/test/rustdoc/issue-34025.rs b/src/test/rustdoc/issue-34025.rs
new file mode 100644
index 0000000000000..8c0a7703c91da
--- /dev/null
+++ b/src/test/rustdoc/issue-34025.rs
@@ -0,0 +1,22 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![crate_name = "foo"]
+
+// @!has 'foo/sys/index.html'
+// @!has 'foo/sys/sidebar-items.js'
+#[doc(hidden)]
+pub mod sys {
+    extern "C" {
+        // @!has 'foo/sys/fn.foo.html'
+        #[doc(hidden)]
+        pub fn foo();
+    }
+}