Finish converting existing comments for internal API docs (#8146)

* Finish converting existing comments for internal API docs

99% of this was just reformatting existing comments. Only two exceptions:

- Expanded upon `BuildResult::status` compat note

- Split up file-level `symbol-table.hh` doc comments to get
  per-definition docs

Also fixed a few whitespace goofs, turning leading tabs to spaces and
removing trailing spaces.

Picking up from #8133

* Fix two things from comments

* Use triple-backtick not indent for `dumpPath`

* Convert GNU-style `\`..'` quotes to markdown style in API docs

This will render correctly.

1 files changed, 95 insertions, 50 deletions

diff --git a/src/libstore/local-store.hh b/src/libstore/local-store.hh
index 7e0849961..55add18dd 100644
--- a/src/libstore/local-store.hh
+++ b/src/libstore/local-store.hh
@@ -19,10 +19,14 @@
 namespace nix {
 
 
-/* Nix store and database schema version.  Version 1 (or 0) was Nix <=
-   0.7.  Version 2 was Nix 0.8 and 0.9.  Version 3 is Nix 0.10.
-   Version 4 is Nix 0.11.  Version 5 is Nix 0.12-0.16.  Version 6 is
-   Nix 1.0.  Version 7 is Nix 1.3. Version 10 is 2.0. */
+/**
+ * Nix store and database schema version.
+ *
+ * Version 1 (or 0) was Nix <=
+ * 0.7.  Version 2 was Nix 0.8 and 0.9.  Version 3 is Nix 0.10.
+ * Version 4 is Nix 0.11.  Version 5 is Nix 0.12-0.16.  Version 6 is
+ * Nix 1.0.  Version 7 is Nix 1.3. Version 10 is 2.0.
+ */
 const int nixSchemaVersion = 10;
 
 
@@ -51,30 +55,40 @@ class LocalStore : public virtual LocalStoreConfig, public virtual LocalFSStore,
 {
 private:
 
-    /* Lock file used for upgrading. */
+    /**
+     * Lock file used for upgrading.
+     */
     AutoCloseFD globalLock;
 
     struct State
     {
-        /* The SQLite database object. */
+        /**
+         * The SQLite database object.
+         */
         SQLite db;
 
         struct Stmts;
         std::unique_ptr<Stmts> stmts;
 
-        /* The last time we checked whether to do an auto-GC, or an
-           auto-GC finished. */
+        /**
+         * The last time we checked whether to do an auto-GC, or an
+         * auto-GC finished.
+         */
         std::chrono::time_point<std::chrono::steady_clock> lastGCCheck;
 
-        /* Whether auto-GC is running. If so, get gcFuture to wait for
-           the GC to finish. */
+        /**
+         * Whether auto-GC is running. If so, get gcFuture to wait for
+         * the GC to finish.
+         */
         bool gcRunning = false;
         std::shared_future<void> gcFuture;
 
-        /* How much disk space was available after the previous
-           auto-GC. If the current available disk space is below
-           minFree but not much below availAfterGC, then there is no
-           point in starting a new GC. */
+        /**
+         * How much disk space was available after the previous
+         * auto-GC. If the current available disk space is below
+         * minFree but not much below availAfterGC, then there is no
+         * point in starting a new GC.
+         */
         uint64_t availAfterGC = std::numeric_limits<uint64_t>::max();
 
         std::unique_ptr<PublicKeys> publicKeys;
@@ -97,11 +111,15 @@ private:
 
 public:
 
-    // Hack for build-remote.cc.
+    /**
+     * Hack for build-remote.cc.
+     */
     PathSet locksHeld;
 
-    /* Initialise the local store, upgrading the schema if
-       necessary. */
+    /**
+     * Initialise the local store, upgrading the schema if
+     * necessary.
+     */
     LocalStore(const Params & params);
     LocalStore(std::string scheme, std::string path, const Params & params);
 
@@ -110,7 +128,9 @@ public:
     static std::set<std::string> uriSchemes()
     { return {}; }
 
-    /* Implementations of abstract store API methods. */
+    /**
+     * Implementations of abstract store API methods.
+     */
 
     std::string getUri() override;
 
@@ -155,13 +175,19 @@ private:
 
     void createTempRootsFile();
 
-    /* The file to which we write our temporary roots. */
+    /**
+     * The file to which we write our temporary roots.
+     */
     Sync<AutoCloseFD> _fdTempRoots;
 
-    /* The global GC lock. */
+    /**
+     * The global GC lock.
+     */
     Sync<AutoCloseFD> _fdGCLock;
 
-    /* Connection to the garbage collector. */
+    /**
+     * Connection to the garbage collector.
+     */
     Sync<AutoCloseFD> _fdRootsSocket;
 
 public:
@@ -180,24 +206,30 @@ public:
 
     void collectGarbage(const GCOptions & options, GCResults & results) override;
 
-    /* Optimise the disk space usage of the Nix store by hard-linking
-       files with the same contents. */
+    /**
+     * Optimise the disk space usage of the Nix store by hard-linking
+     * files with the same contents.
+     */
     void optimiseStore(OptimiseStats & stats);
 
     void optimiseStore() override;
 
-    /* Optimise a single store path. Optionally, test the encountered
-       symlinks for corruption. */
+    /**
+     * Optimise a single store path. Optionally, test the encountered
+     * symlinks for corruption.
+     */
     void optimisePath(const Path & path, RepairFlag repair);
 
     bool verifyStore(bool checkContents, RepairFlag repair) override;
 
-    /* Register the validity of a path, i.e., that `path' exists, that
-       the paths referenced by it exists, and in the case of an output
-       path of a derivation, that it has been produced by a successful
-       execution of the derivation (or something equivalent).  Also
-       register the hash of the file system contents of the path.  The
-       hash must be a SHA-256 hash. */
+    /**
+     * Register the validity of a path, i.e., that `path` exists, that
+     * the paths referenced by it exists, and in the case of an output
+     * path of a derivation, that it has been produced by a successful
+     * execution of the derivation (or something equivalent).  Also
+     * register the hash of the file system contents of the path.  The
+     * hash must be a SHA-256 hash.
+     */
     void registerValidPath(const ValidPathInfo & info);
 
     void registerValidPaths(const ValidPathInfos & infos);
@@ -212,12 +244,16 @@ public:
 
     void addSignatures(const StorePath & storePath, const StringSet & sigs) override;
 
-    /* If free disk space in /nix/store if below minFree, delete
-       garbage until it exceeds maxFree. */
+    /**
+     * If free disk space in /nix/store if below minFree, delete
+     * garbage until it exceeds maxFree.
+     */
     void autoGC(bool sync = true);
 
-    /* Register the store path 'output' as the output named 'outputName' of
-       derivation 'deriver'. */
+    /**
+     * Register the store path 'output' as the output named 'outputName' of
+     * derivation 'deriver'.
+     */
     void registerDrvOutput(const Realisation & info) override;
     void registerDrvOutput(const Realisation & info, CheckSigsFlag checkSigs) override;
     void cacheDrvOutputMapping(
@@ -247,7 +283,9 @@ private:
 
     void invalidatePath(State & state, const StorePath & path);
 
-    /* Delete a path from the Nix store. */
+    /**
+     * Delete a path from the Nix store.
+     */
     void invalidatePathChecked(const StorePath & path);
 
     void verifyPath(const Path & path, const StringSet & store,
@@ -280,8 +318,10 @@ private:
     bool isValidPath_(State & state, const StorePath & path);
     void queryReferrers(State & state, const StorePath & path, StorePathSet & referrers);
 
-    /* Add signatures to a ValidPathInfo or Realisation using the secret keys
-       specified by the ‘secret-key-files’ option. */
+    /**
+     * Add signatures to a ValidPathInfo or Realisation using the secret keys
+     * specified by the ‘secret-key-files’ option.
+     */
     void signPathInfo(ValidPathInfo & info);
     void signRealisation(Realisation &);
 
@@ -311,18 +351,23 @@ typedef std::pair<dev_t, ino_t> Inode;
 typedef std::set<Inode> InodesSeen;
 
 
-/* "Fix", or canonicalise, the meta-data of the files in a store path
-   after it has been built.  In particular:
-   - the last modification date on each file is set to 1 (i.e.,
-     00:00:01 1/1/1970 UTC)
-   - the permissions are set of 444 or 555 (i.e., read-only with or
-     without execute permission; setuid bits etc. are cleared)
-   - the owner and group are set to the Nix user and group, if we're
-     running as root.
-   If uidRange is not empty, this function will throw an error if it
-   encounters files owned by a user outside of the closed interval
-   [uidRange->first, uidRange->second].
-*/
+/**
+ * "Fix", or canonicalise, the meta-data of the files in a store path
+ * after it has been built.  In particular:
+ *
+ * - the last modification date on each file is set to 1 (i.e.,
+ *   00:00:01 1/1/1970 UTC)
+ *
+ * - the permissions are set of 444 or 555 (i.e., read-only with or
+ *   without execute permission; setuid bits etc. are cleared)
+ *
+ * - the owner and group are set to the Nix user and group, if we're
+ *   running as root.
+ *
+ * If uidRange is not empty, this function will throw an error if it
+ * encounters files owned by a user outside of the closed interval
+ * [uidRange->first, uidRange->second].
+ */
 void canonicalisePathMetaData(
     const Path & path,
     std::optional<std::pair<uid_t, uid_t>> uidRange,