debugger: Add memory view (#33955)

This is mostly setting up the UI for now; I expect it to be the biggest
chunk of work.

Release Notes:

- debugger: Added memory view

---------

Co-authored-by: Anthony Eid <hello@anthonyeid.me>
Co-authored-by: Mikayla Maki <mikayla.c.maki@gmail.com>
Co-authored-by: Mikayla Maki <mikayla@zed.dev>

crates/project/src/debugger/dap_command.rs

@@ -1,6 +1,7 @@
 use std::sync::Arc;
 
 use anyhow::{Context as _, Ok, Result};
+use base64::Engine;
 use dap::{
     Capabilities, ContinueArguments, ExceptionFilterOptions, InitializeRequestArguments,
     InitializeRequestArgumentsPathFormat, NextArguments, SetVariableResponse, SourceBreakpoint,
@@ -1774,3 +1775,95 @@ impl DapCommand for LocationsCommand {
         })
     }
 }
+
+#[derive(Debug, Hash, PartialEq, Eq)]
+pub(crate) struct ReadMemory {
+    pub(crate) memory_reference: String,
+    pub(crate) offset: Option<u64>,
+    pub(crate) count: u64,
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub(crate) struct ReadMemoryResponse {
+    pub(super) address: Arc<str>,
+    pub(super) unreadable_bytes: Option<u64>,
+    pub(super) content: Arc<[u8]>,
+}
+
+impl LocalDapCommand for ReadMemory {
+    type Response = ReadMemoryResponse;
+    type DapRequest = dap::requests::ReadMemory;
+    const CACHEABLE: bool = true;
+
+    fn is_supported(capabilities: &Capabilities) -> bool {
+        capabilities
+            .supports_read_memory_request
+            .unwrap_or_default()
+    }
+    fn to_dap(&self) -> <Self::DapRequest as dap::requests::Request>::Arguments {
+        dap::ReadMemoryArguments {
+            memory_reference: self.memory_reference.clone(),
+            offset: self.offset,
+            count: self.count,
+        }
+    }
+
+    fn response_from_dap(
+        &self,
+        message: <Self::DapRequest as dap::requests::Request>::Response,
+    ) -> Result<Self::Response> {
+        let data = if let Some(data) = message.data {
+            base64::engine::general_purpose::STANDARD
+                .decode(data)
+                .log_err()
+                .context("parsing base64 data from DAP's ReadMemory response")?
+        } else {
+            vec![]
+        };
+
+        Ok(ReadMemoryResponse {
+            address: message.address.into(),
+            content: data.into(),
+            unreadable_bytes: message.unreadable_bytes,
+        })
+    }
+}
+
+impl LocalDapCommand for dap::DataBreakpointInfoArguments {
+    type Response = dap::DataBreakpointInfoResponse;
+    type DapRequest = dap::requests::DataBreakpointInfo;
+    const CACHEABLE: bool = true;
+    fn is_supported(capabilities: &Capabilities) -> bool {
+        capabilities.supports_data_breakpoints.unwrap_or_default()
+    }
+    fn to_dap(&self) -> <Self::DapRequest as dap::requests::Request>::Arguments {
+        self.clone()
+    }
+
+    fn response_from_dap(
+        &self,
+        message: <Self::DapRequest as dap::requests::Request>::Response,
+    ) -> Result<Self::Response> {
+        Ok(message)
+    }
+}
+
+impl LocalDapCommand for dap::WriteMemoryArguments {
+    type Response = dap::WriteMemoryResponse;
+    type DapRequest = dap::requests::WriteMemory;
+    fn is_supported(capabilities: &Capabilities) -> bool {
+        capabilities
+            .supports_write_memory_request
+            .unwrap_or_default()
+    }
+    fn to_dap(&self) -> <Self::DapRequest as dap::requests::Request>::Arguments {
+        self.clone()
+    }
+
+    fn response_from_dap(
+        &self,
+        message: <Self::DapRequest as dap::requests::Request>::Response,
+    ) -> Result<Self::Response> {
+        Ok(message)
+    }
+}