mostly implement getting a running process

src/process.rs

@@ -0,0 +1,50 @@
+use crate::{handle::Handle, snapshot};
+
+use derive_more::derive::Display;
+
+#[derive(Debug, Default)]
+pub struct Process {
+    name: String,
+    id: u32,
+    base_address: usize,
+    handle: Handle,
+}
+
+#[derive(Display)]
+pub enum Identifier {
+    Id(u32),
+    Name(String),
+}
+
+impl Process {
+    pub fn from(identifier: &Identifier) -> Result<Self, crate::Error> {
+        let snapshot = match identifier {
+            Identifier::Id(pid) => snapshot::Process::get_processes()?
+                .into_iter()
+                .find(|snapshot| snapshot.id == *pid),
+            Identifier::Name(ref name) => snapshot::Process::get_processes()?
+                .into_iter()
+                .find(|snapshot| snapshot.name == *name),
+        };
+        let Some(snapshot) = snapshot else {
+            return Err(crate::Error::ProcessError(format!(
+                "couldn't find a process with identifier `{identifier}`",
+            )));
+        };
+        let process = Self {
+            name: snapshot.name,
+            id: snapshot.id,
+            base_address: 0,
+            handle: Handle::from_pid(snapshot.id)?,
+        };
+        Ok(process)
+    }
+
+    pub fn with_pid(pid: u32) -> Result<Self, crate::Error> {
+        Self::from(&Identifier::Id(pid))
+    }
+
+    pub fn with_name(name: &str) -> Result<Self, crate::Error> {
+        Self::from(&Identifier::Name(name.to_string()))
+    }
+}