From 7d48fcf38292ab80a59e26fd1b2d0bb0df0afcf5 Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jackpot51@gmail.com>
Date: Sat, 16 Apr 2016 13:33:21 -0600
Subject: [PATCH] WIP: Add truncate

---
 fuse/main.rs       |  6 ++++--
 scheme/resource.rs |  8 ++++----
 scheme/scheme.rs   |  2 +-
 src/filesystem.rs  | 30 ++++++++++++++++++++++++++++++
 4 files changed, 39 insertions(+), 7 deletions(-)

diff --git a/fuse/main.rs b/fuse/main.rs
index d557918276..fb44f35a35 100644
--- a/fuse/main.rs
+++ b/fuse/main.rs
@@ -83,11 +83,13 @@ impl Filesystem for RedoxFS {
     }
 
     fn setattr(&mut self, _req: &Request, block: u64, _mode: Option<u32>,
-                _uid: Option<u32>, _gid: Option<u32>, _size: Option<u64>,
+                _uid: Option<u32>, _gid: Option<u32>, size: Option<u64>,
                 _atime: Option<Timespec>, _mtime: Option<Timespec>, _fh: Option<u64>,
                 _crtime: Option<Timespec>, _chgtime: Option<Timespec>, _bkuptime: Option<Timespec>,
                 _flags: Option<u32>, reply: ReplyAttr) {
-        //TODO: Implement truncate
+        /*if let Some(truncate_size) = size {
+            try!(self.fs.node_set_len(truncate_size));
+        }*/
         match self.fs.node(block) {
             Ok(node) => {
                 reply.attr(&TTL, &FileAttr {
diff --git a/scheme/resource.rs b/scheme/resource.rs
index 52e907ec37..7c8b3c06ba 100644
--- a/scheme/resource.rs
+++ b/scheme/resource.rs
@@ -18,7 +18,7 @@ pub trait Resource {
 
     fn sync(&mut self) -> Result<usize>;
 
-    fn truncate(&mut self, len: usize) -> Result<usize>;
+    fn truncate(&mut self, len: usize, fs: &mut FileSystem) -> Result<usize>;
 }
 
 pub struct DirResource {
@@ -82,7 +82,7 @@ impl Resource for DirResource {
         Err(Error::new(EINVAL))
     }
 
-    fn truncate(&mut self, _len: usize) -> Result<usize> {
+    fn truncate(&mut self, _len: usize, _fs: &mut FileSystem) -> Result<usize> {
         Err(Error::new(EINVAL))
     }
 }
@@ -152,7 +152,7 @@ impl Resource for FileResource {
         Ok(0)
     }
 
-    fn truncate(&mut self, len: usize) -> Result<usize> {
-        Ok(0)
+    fn truncate(&mut self, len: usize, fs: &mut FileSystem) -> Result<usize> {
+        fs.node_set_len(self.block, len as u64).and(Ok(0))
     }
 }
diff --git a/scheme/scheme.rs b/scheme/scheme.rs
index 8af7985692..d90351588a 100644
--- a/scheme/scheme.rs
+++ b/scheme/scheme.rs
@@ -230,7 +230,7 @@ impl Scheme for FileScheme {
     fn ftruncate(&mut self, id: usize, len: usize) -> Result<usize> {
         // println!("Ftruncate {}, {}", id, len);
         if let Some(mut file) = self.files.get_mut(&id) {
-            file.truncate(len)
+            file.truncate(len, &mut self.fs)
         } else {
             Err(Error::new(EBADF))
         }
diff --git a/src/filesystem.rs b/src/filesystem.rs
index 4252eebaa4..f9191dc177 100644
--- a/src/filesystem.rs
+++ b/src/filesystem.rs
@@ -323,6 +323,36 @@ impl FileSystem {
         }
     }
 
+    pub fn node_set_len(&mut self, block: u64, mut length: u64) -> Result<()> {
+        if block == 0 {
+            return Err(Error::new(ENOENT));
+        }
+
+        let mut changed = false;
+
+        let mut node = try!(self.node(block));
+        for mut extent in node.1.extents.iter_mut() {
+            if extent.length > length {
+                //TODO: try!(self.deallocate(block, 512));
+                extent.length = length;
+                changed = true;
+                length = 0;
+            } else {
+                length -= extent.length;
+            }
+        }
+
+        if changed {
+            try!(self.write_at(node.0, &node.1));
+        }
+
+        if node.1.next > 0 {
+            self.node_set_len(node.1.next, length)
+        } else {
+            Ok(())
+        }
+    }
+
     fn node_extents(&mut self, block: u64, mut offset: u64, mut len: usize, extents: &mut Vec<Extent>) -> Result<()> {
         if block == 0 {
             return Ok(());