feat: create commitTemplate.ts

Author: MichaelCurrin

src/git/commitTemplate.ts

@@ -0,0 +1,98 @@
+/**
+ * Commit template module.
+ *
+ * TODO: Move to docs and link there.
+ *
+ * Read the message from the a configured commit template file and use it as a prefix in the message.
+ *
+ * A commit template is built-in Git behavior to see a value for the start of each commit message. This is useful if you have a ticket number, project name, or similar to add at the start of each commit.
+ *
+ * Note that VS Code and Git CLI both automatically read from this file when generating a commit. However, the value is hard to use. There is behavior in this extension to move the old message to the end and enter a commit type prefix and commit message before it, but there is no way to know from the content of the message for sure whether the old message is a commit template value or just a hand-typed message.
+ *
+ * To avoid making an extra config value for the extension that one has to manage say in a Settings file or internal data, the approach is rather to use the existing commit template pattern in Git.
+ */
+import * as fs from 'fs';
+import * as path from 'path';
+import { getWorkspaceFolder } from "../workspace";
+import { execute } from "./cli";
+
+const CONFIG_SUBCOMMAND = "config"
+const COMMIT_TEMPLATE_IDENTIFIER = 'commit.template'
+
+/**
+ * Get a value from the Git config.
+ *
+ * The CLI will assume local (project) project by default.
+ */
+export async function _getConfigValue(options: string[]) {
+  const workspace = getWorkspaceFolder()
+  const { stdout, stderr } = await execute(
+    workspace,
+    CONFIG_SUBCOMMAND,
+    options
+  );
+
+  if (stderr) {
+    console.debug(`stderr for 'git ${CONFIG_SUBCOMMAND}' command:`, stderr);
+  }
+
+  return stdout
+}
+
+/**
+ * Get commit template path.
+ *
+ * Get the configured value for a commit template path if set.
+ */
+async function _getCommitTemplatePath() {
+  try {
+    const options = [COMMIT_TEMPLATE_IDENTIFIER]
+    return await _getConfigValue(options)
+  } catch (_e) {
+    return null
+  }
+}
+
+/**
+ * Read a file.
+ *
+ * NB. Use current workspace as the base path.
+ */
+function _readFile(filePath: string) {
+  const workspace = getWorkspaceFolder()
+  const p = path.join(workspace, filePath)
+
+  let value
+
+  try {
+    value = fs.readFileSync(p, "utf-8")
+  } catch (err) {
+    console.error(`Could not find template file: ${p}. ${err.toString()}`)
+
+    return null
+  }
+
+  if (!value) {
+    return null
+  }
+
+  console.debug(`Read ${p} and found: ${value}`)
+
+  return value
+}
+
+/**
+ * Get value of commit template file.
+ *
+ * Return null if file is not configured or file is missing, without aborting.
+ */
+export async function getCommitTemplateValue() {
+  const filePath = await _getCommitTemplatePath()
+
+  if (!filePath) {
+    console.error(`Could not read missing file: ${filePath}`)
+    return null
+  }
+
+  return _readFile(filePath)
+}