Add basic context menu to all views

Users can opt-out by setting `disable_context_menus: false` in their
GitSavvy settings.

Context.sublime-menu

@@ -0,0 +1,38 @@
+[
+    {
+        "caption": "GitSavvy: Line History",
+        "command": "gs_ctx_line_history"
+    },
+    {
+        "caption": "GitSavvy: Pick-axe",
+        "command": "gs_ctx_pick_axe"
+    },
+    {
+        "caption": "GitSavvy: Stage selected hunk",
+        "command": "gs_ctx_stage_hunk"
+    }
+    // {
+    //     "caption": "    ...",
+    //     "children": [
+    //         {
+    //             "caption": "Repo History",
+    //             "command": "gs_graph",
+    //             "args": { "all": true }
+    //         },
+    //         {
+    //             "caption": "Path History",
+    //             "command": "gs_graph_current_path"
+    //         },
+    //         {
+    //             "caption": "File History",
+    //             "command": "gs_graph_current_file",
+    //             "args": { "all": false }
+    //         },
+    //         { "caption": "-" },
+    //         {
+    //             "caption": "Show current file revision at HEAD",
+    //             "command": "gs_show_file_at_commit"
+    //         },
+    //     ]
+    // },
+]

GitSavvy.sublime-settings

@@ -369,5 +369,11 @@
         When set to `true`, no views will receive the prompt asking to initialize
         Git in the current view's directory when not found.
      */
-    "disable_git_init_prompt": false
+    "disable_git_init_prompt": false,
+
+    /*
+        Disable adding any entries to the context menu available when right-clicking
+        in any view.
+    */
+    "disable_context_menus": false
 }

core/commands/__init__.py

@@ -7,6 +7,7 @@
 from .cherry_pick import *
 from .commit import *
 from .commit_compare import *
+from .context_menu import *
 from .custom import *
 from .diff import *
 from .fetch import *

core/commands/context_menu.py

@@ -0,0 +1,111 @@
+from functools import lru_cache
+
+import sublime
+
+from GitSavvy.core.base_commands import GsTextCommand
+
+from typing import Callable, List, Optional, TypeVar
+T = TypeVar("T")
+
+__all__ = (
+    "gs_ctx_line_history",
+    "gs_ctx_pick_axe",
+    "gs_ctx_stage_hunk",
+)
+
+
+# Provide a `CommandContext` as the global `Context` which
+# is valid for this exact "runtime-task".  This is to speed-up
+# the preconditions in `is_enabled` and `is_visible`.
+
+def cached_property(fn: Callable[..., T]) -> T:
+    return property(lru_cache(1)(fn))  # type: ignore[return-value]
+
+
+class CommandContext:
+    def __init__(self, cmd: GsTextCommand):
+        self._cmd = cmd
+
+    @cached_property
+    def enabled(self) -> bool:
+        return not self._cmd.savvy_settings.get("disable_context_menus")
+
+    @cached_property
+    def sel(self) -> List[sublime.Region]:
+        return list(self._cmd.view.sel())
+
+    @cached_property
+    def repo_path(self) -> Optional[str]:
+        return self._cmd.find_repo_path()
+
+    @cached_property
+    def file_path(self) -> Optional[str]:
+        return self._cmd.file_path
+
+
+Context = None
+
+
+def get_context(self) -> CommandContext:
+    global Context
+    if not Context:
+        Context = CommandContext(self)
+        sublime.set_timeout(reset_context)
+
+    return Context
+
+
+def reset_context():
+    global Context
+    Context = None
+
+
+class gs_ctx_line_history(GsTextCommand):
+    def is_enabled(self) -> bool:
+        ctx = get_context(self)
+        return bool(
+            ctx.sel
+            and ctx.repo_path
+        )
+
+    def is_visible(self) -> bool:
+        ctx = get_context(self)
+        return ctx.enabled and bool(ctx.repo_path)
+
+    def run(self, edit) -> None:
+        self.view.run_command("gs_line_history")
+
+
+class gs_ctx_stage_hunk(GsTextCommand):
+    def is_enabled(self) -> bool:
+        ctx = get_context(self)
+        return bool(
+            ctx.sel
+            and ctx.repo_path
+            and self.view.file_name()
+            and not self.view.is_dirty()
+        )
+
+    def is_visible(self) -> bool:
+        ctx = get_context(self)
+        return ctx.enabled and bool(ctx.repo_path)
+
+    def run(self, edit) -> None:
+        self.view.run_command("gs_stage_hunk")
+
+
+class gs_ctx_pick_axe(GsTextCommand):
+    def is_enabled(self) -> bool:
+        ctx = get_context(self)
+        return bool(
+            ctx.sel
+            and ctx.repo_path
+            and all(self.view.substr(r).strip() for r in ctx.sel)
+        )
+
+    def is_visible(self) -> bool:
+        ctx = get_context(self)
+        return ctx.enabled and bool(ctx.repo_path)
+
+    def run(self, edit) -> None:
+        self.view.run_command("gs_graph_pickaxe")