bug: Fix bugs with disk widget and disk encryption (#423)

Two issues were highlighted as a result of using either Void Linux with disk encryption, or just disk encryption on Linux in general:

Two fixes:
1. Fixes a failed `usage()` call in the `get_disk_usage` function from failing the entire result.  Now it only returns an entry with N/A results.  This occurred in some distros and disk encryption setups, for example, the one for Void Linux here: https://docs.voidlinux.org/installation/guides/fde.html.

2. Fixes a potential mapping issue with disk encryption on Linux in general.  Since the disk might map to `/dev/mapper/whatever`, but the I/O harvester was using another name, the mappings would not match.  As such, we now also check if a symlink exists; if it does, then we take it and work out the correct path.  This also fixes the disk name being wrong.

4 files changed, 88 insertions, 28 deletions

diff --git a/.vscode/settings.json b/.vscode/settings.json
index 2c88c1a2..a04896e8 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -18,6 +18,7 @@
     "GIGA",
     "Hamberg",
     "KIBI",
+    "LUKS",
     "Lukas",
     "MEBI",
     "MEBIBYTE",
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1b1ca437..3176e72b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -41,6 +41,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - [#417](https://github.com/ClementTsang/bottom/pull/417): Fixes the sort menu and sort shortcuts not syncing up.
 
+- [#423](https://github.com/ClementTsang/bottom/pull/423): Fixes disk encryption causing the disk widget to fail or not properly map I/O statistics.
+
 ## [0.5.7] - 2021-01-30
 
 ## Bug Fixes
diff --git a/src/app/data_harvester/disks.rs b/src/app/data_harvester/disks.rs
index 5a67a909..246f5b5d 100644
--- a/src/app/data_harvester/disks.rs
+++ b/src/app/data_harvester/disks.rs
@@ -4,9 +4,9 @@ use crate::app::Filter;
 pub struct DiskHarvest {
     pub name: String,
     pub mount_point: String,
-    pub free_space: u64,
-    pub used_space: u64,
-    pub total_space: u64,
+    pub free_space: Option<u64>,
+    pub used_space: Option<u64>,
+    pub total_space: Option<u64>,
 }
 
 #[derive(Clone, Debug)]
@@ -35,7 +35,6 @@ pub async fn get_io_usage(actually_get: bool) -> crate::utils::error::Result<Opt
             let mount_point = io.device_name().to_str().unwrap_or("Name Unavailable");
 
             // FIXME: [MOUNT POINT] Add the filter here I guess?
-
             io_hash.insert(
                 mount_point.to_string(),
                 Some(IOData {
@@ -64,11 +63,43 @@ pub async fn get_disk_usage(
 
     while let Some(part) = partitions_stream.next().await {
         if let Ok(partition) = part {
-            let name = (partition
-                .device()
-                .unwrap_or_else(|| std::ffi::OsStr::new("Name Unavailable"))
-                .to_str()
-                .unwrap_or("Name Unavailable"))
+            let symlink: std::ffi::OsString;
+
+            let name = (if let Some(device) = partition.device() {
+                // See if this disk is actually mounted elsewhere on Linux...
+                // This is a workaround to properly map I/O in some cases (i.e. disk encryption), see
+                // https://github.com/ClementTsang/bottom/issues/419
+                if cfg!(target_os = "linux") {
+                    if let Ok(path) = std::fs::read_link(device) {
+                        if path.is_absolute() {
+                            symlink = path.into_os_string();
+                            symlink.as_os_str()
+                        } else {
+                            let mut combined_path = std::path::PathBuf::new();
+                            combined_path.push(device);
+                            combined_path.pop(); // Pop the current file...
+                            combined_path.push(path.clone());
+
+                            if let Ok(path) = std::fs::canonicalize(combined_path) {
+                                // Resolve the local path into an absolute one...
+                                symlink = path.into_os_string();
+                                symlink.as_os_str()
+                            } else {
+                                symlink = path.into_os_string();
+                                symlink.as_os_str()
+                            }
+                        }
+                    } else {
+                        device
+                    }
+                } else {
+                    device
+                }
+            } else {
+                std::ffi::OsStr::new("Name Unavailable")
+            }
+            .to_str()
+            .unwrap_or("Name Unavailable"))
             .to_string();
 
             let mount_point = (partition
@@ -91,14 +122,24 @@ pub async fn get_disk_usage(
             };
 
             if to_keep {
-                let usage = heim::disk::usage(partition.mount_point().to_path_buf()).await?;
-                vec_disks.push(DiskHarvest {
-                    free_space: usage.free().get::<heim::units::information::byte>(),
-                    used_space: usage.used().get::<heim::units::information::byte>(),
-                    total_space: usage.total().get::<heim::units::information::byte>(),
-                    mount_point,
-                    name,
-                });
+                // The usage line fails in some cases (Void linux + LUKS, see https://github.com/ClementTsang/bottom/issues/419)
+                if let Ok(usage) = heim::disk::usage(partition.mount_point().to_path_buf()).await {
+                    vec_disks.push(DiskHarvest {
+                        free_space: Some(usage.free().get::<heim::units::information::byte>()),
+                        used_space: Some(usage.used().get::<heim::units::information::byte>()),
+                        total_space: Some(usage.total().get::<heim::units::information::byte>()),
+                        mount_point,
+                        name,
+                    });
+                } else {
+                    vec_disks.push(DiskHarvest {
+                        free_space: None,
+                        used_space: None,
+                        total_space: None,
+                        mount_point,
+                        name,
+                    });
+                }
             }
         }
     }
diff --git a/src/data_conversion.rs b/src/data_conversion.rs
index 57698b7f..b3614cf1 100644
--- a/src/data_conversion.rs
+++ b/src/data_conversion.rs
@@ -116,20 +116,36 @@ pub fn convert_disk_row(current_data: &data_farmer::DataCollection) -> Vec<Vec<S
         .iter()
         .zip(&current_data.io_labels)
         .for_each(|(disk, (io_read, io_write))| {
-            let converted_free_space = get_simple_byte_values(disk.free_space, false);
-            let converted_total_space = get_simple_byte_values(disk.total_space, false);
-            disk_vector.push(vec![
-                disk.name.to_string(),
-                disk.mount_point.to_string(),
-                format!(
-                    "{:.0}%",
-                    disk.used_space as f64 / disk.total_space as f64 * 100_f64
-                ),
-                format!("{:.*}{}", 0, converted_free_space.0, converted_free_space.1),
+            let free_space_fmt = if let Some(free_space) = disk.free_space {
+                let converted_free_space = get_simple_byte_values(free_space, false);
+                format!("{:.*}{}", 0, converted_free_space.0, converted_free_space.1)
+            } else {
+                "N/A".to_string()
+            };
+            let total_space_fmt = if let Some(total_space) = disk.total_space {
+                let converted_total_space = get_simple_byte_values(total_space, false);
                 format!(
                     "{:.*}{}",
                     0, converted_total_space.0, converted_total_space.1
-                ),
+                )
+            } else {
+                "N/A".to_string()
+            };
+
+            let usage_fmt = if let (Some(used_space), Some(total_space)) =
+                (disk.used_space, disk.total_space)
+            {
+                format!("{:.0}%", used_space as f64 / total_space as f64 * 100_f64)
+            } else {
+                "N/A".to_string()
+            };
+
+            disk_vector.push(vec![
+                disk.name.to_string(),
+                disk.mount_point.to_string(),
+                usage_fmt,
+                free_space_fmt,
+                total_space_fmt,
                 io_read.to_string(),
                 io_write.to_string(),
             ]);