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-rw-r--r--meap/meap-code/ch3/ch3-files-with-modes.rs75
1 files changed, 75 insertions, 0 deletions
diff --git a/meap/meap-code/ch3/ch3-files-with-modes.rs b/meap/meap-code/ch3/ch3-files-with-modes.rs
new file mode 100644
index 0000000..4440924
--- /dev/null
+++ b/meap/meap-code/ch3/ch3-files-with-modes.rs
@@ -0,0 +1,75 @@
+#[derive(Debug)]
+pub enum FileOpenMode {
+ Read,
+ Write,
+ Append,
+ Truncate,
+}
+
+#[derive(Debug)]
+pub enum FileHandle {
+ Handle(usize),
+ None,
+}
+
+#[derive(Debug)]
+pub enum FileState {
+ PendingCreation,
+ Created(FileOpenMode),
+ Opened(FileOpenMode),
+ Error(String),
+ Closed,
+ Deleted,
+}
+
+#[derive(Debug)]
+pub struct File {
+ name: String,
+ data: Vec<u8>,
+ state: FileState,
+ handle: FileHandle,
+}
+
+impl File {
+ pub fn new(name: &str) -> File {
+ File {
+ name: String::from(name),
+ data: Vec::new(),
+ state: FileState::PendingCreation, // <1>
+ handle: FileHandle::None, // <1>
+ }
+ }
+
+ pub fn from_options(name: &str, state: FileState, handle: FileHandle) -> File {
+ File {
+ name: String::from(name),
+ data: Vec::new(),
+ state: state,
+ handle: handle,
+ }
+ }
+}
+
+fn main() {
+ let f1 = File::new("f1.txt");
+ let f2 = File::from_options("f2.txt",
+ FileState::Opened(FileOpenMode::Read),
+ FileHandle::Handle(123)
+ );
+ let f3 = File::from_options("f3.txt",
+ FileState::Opened(FileOpenMode::Write),
+ FileHandle::None
+ );
+
+ let mut files = [f1, f2, f3];
+
+ for f in &files {
+ println!("{:?}", f);
+ }
+
+ // uh oh, disk failure
+ for ref mut f in &mut files {
+ f.state = FileState::Error(String::from("disk read failure"));
+ println!("{:?}", f);
+ }
+} \ No newline at end of file