Expose cargo add internals as utils

Move cargo add utils out for future use by other subcommands (namely cargo
remove, per rust-lang#10520).

src/bin/cargo/commands/add.rs

@@ -6,10 +6,10 @@ use cargo::core::FeatureValue;
 use cargo::ops::cargo_add::add;
 use cargo::ops::cargo_add::AddOptions;
 use cargo::ops::cargo_add::DepOp;
-use cargo::ops::cargo_add::DepTable;
 use cargo::ops::resolve_ws;
 use cargo::util::command_prelude::*;
 use cargo::util::interning::InternedString;
+use cargo::util::toml_mut::manifest::DepTable;
 use cargo::CargoResult;
 
 pub fn cli() -> clap::Command<'static> {

src/cargo/ops/cargo_add/crate_spec.rs

@@ -3,7 +3,7 @@
 use anyhow::Context as _;
 
 use super::Dependency;
-use super::RegistrySource;
+use crate::util::toml_mut::dependency::RegistrySource;
 use crate::util::validate_package_name;
 use crate::CargoResult;
 

src/cargo/ops/cargo_add/mod.rs

@@ -1,8 +1,6 @@
 //! Core of cargo-add command
 
 mod crate_spec;
-mod dependency;
-mod manifest;
 
 use std::collections::BTreeMap;
 use std::collections::BTreeSet;
@@ -26,18 +24,17 @@ use crate::core::Registry;
 use crate::core::Shell;
 use crate::core::Summary;
 use crate::core::Workspace;
+use crate::util::toml_mut::dependency::Dependency;
+use crate::util::toml_mut::dependency::GitSource;
+use crate::util::toml_mut::dependency::MaybeWorkspace;
+use crate::util::toml_mut::dependency::PathSource;
+use crate::util::toml_mut::dependency::Source;
+use crate::util::toml_mut::dependency::WorkspaceSource;
+use crate::util::toml_mut::manifest::DepTable;
+use crate::util::toml_mut::manifest::LocalManifest;
 use crate::CargoResult;
 use crate::Config;
 use crate_spec::CrateSpec;
-use dependency::Dependency;
-use dependency::GitSource;
-use dependency::PathSource;
-use dependency::RegistrySource;
-use dependency::Source;
-use manifest::LocalManifest;
-
-use crate::ops::cargo_add::dependency::{MaybeWorkspace, WorkspaceSource};
-pub use manifest::DepTable;
 
 /// Information on what dependencies should be added
 #[derive(Clone, Debug)]

src/cargo/util/mod.rs

@@ -57,6 +57,7 @@ pub mod rustc;
 mod semver_ext;
 pub mod to_semver;
 pub mod toml;
+pub mod toml_mut;
 mod vcs;
 mod workspace;
 

src/cargo/ops/cargo_add/dependency.rs → src/cargo/util/toml_mut/dependency.rs

@@ -895,7 +895,7 @@ impl Display for WorkspaceSource {
 mod tests {
     use std::path::Path;
 
-    use crate::ops::cargo_add::manifest::LocalManifest;
+    use crate::util::toml_mut::manifest::LocalManifest;
     use cargo_util::paths;
 
     use super::*;

src/cargo/util/toml_mut/mod.rs

@@ -0,0 +1,4 @@
+//! Utilities for editing Cargo.toml manifests
+
+pub mod dependency;
+pub mod manifest;