2 files changed, 109 insertions, 0 deletions
diff --git a/bin/nixpkgs_dag.py b/bin/nixpkgs_dag.py
new file mode 100755
index 0000000..7b8adea
--- /dev/null
+++ b/bin/nixpkgs_dag.py
@@ -0,0 +1,107 @@
+#!/usr/bin/env python3
+
+# This script is used to evaluate Nixpkgs and store the relationships between
+# derivations and their input derivations in a directed acyclic graph (DAG).
+# The DAG is represented using an adjacency list and saved in a SQLite db
+
+import re
+import subprocess
+import json
+import sqlite3
+from typing import Set
+
+class drv:
+    pname: str
+    input_drvs: Set[str] = set()
+    cursor: sqlite3.Cursor
+
+    def __init__(self, drv_string: str, cursor: sqlite3.Cursor) -> None:
+        self.cursor = cursor
+
+        j = json.loads(drv_string)
+        if 'drvPath' not in j:
+            raise TypeError
+
+        pname = self.pname_from_drv_path(j['drvPath'])
+        print(pname)
+        if pname is None:
+            raise TypeError
+        self.pname = pname
+
+        for input_drv in j['inputDrvs']:
+            pname = self.pname_from_drv_path(input_drv)
+            if pname is not None:
+                self.input_drvs.add(pname)
+
+    def db_push(self):
+        parrent_id = self.rowid_from_pname(self.cursor, self.pname)
+        for input_drv in self.input_drvs:
+            child_id = self.rowid_from_pname(self.cursor, input_drv)
+
+            self.cursor.execute("""
+                INSERT INTO edges (start, end)
+                VALUES (?, ?)
+            """, (parrent_id, child_id))
+
+    @staticmethod
+    def rowid_from_pname(cursor: sqlite3.Cursor, pname: str) -> int:
+        s = cursor.execute("""
+            SELECT pnames.ROWID FROM pnames
+            WHERE pnames.pname = ?
+        """, (pname,))
+        id = s.fetchone()
+        if id:
+            return id[0]
+        
+        s = cursor.execute("""
+            INSERT INTO pnames (pname)
+            VALUES (?)
+        """, (pname,))
+        if s.lastrowid is None:
+            raise TypeError
+
+        return s.lastrowid
+
+    @staticmethod
+    def pname_from_drv_path(drv_path: str) -> str | None:
+        f = open(drv_path, 'r')
+        drv_string = f.readline()
+        match = re.search('"pname","([^"]+)', drv_string)
+        if match is not None:
+            return match.group(1)
+
+if __name__ == '__main__':
+    cmd = [
+        'nix-eval-jobs',
+        '--flake',
+        'github:nixos/nixpkgs#legacyPackages.x86_64-linux'
+    ]
+    proc = subprocess.Popen(cmd, stdout=subprocess.PIPE,
+                            stderr=subprocess.DEVNULL)
+    if proc.stdout is None:
+        raise TypeError
+
+    con = sqlite3.connect('nixpkgs_dag.db')
+    cur = con.cursor()
+    cur.execute("""
+        CREATE TABLE IF NOT EXISTS pnames (
+            pname TEXT NOT NULL UNIQUE
+        )
+    """)
+    cur.execute("""
+        CREATE TABLE IF NOT EXISTS edges (
+            start INTEGER NOT NULL,
+            end NOT NULL,
+            UNIQUE(start, end) ON CONFLICT REPLACE
+        )
+    """)
+
+    for line in proc.stdout:
+        try:
+            d = drv(line.decode('utf-8'), cur)
+            d.db_push()
+        except Exception as e:
+            print(str(e))
+
+    con.commit()
+    con.close()
diff --git a/flake.nix b/flake.nix
index ac2a920..1c05ee4 100644
--- a/flake.nix
+++ b/flake.nix
@@ -49,6 +49,8 @@
               linuxKernel.packages.linux_6_6.perf
               hyperfine
               nix-eval-jobs
+              python3
+              pyright
             ];
 
             shellHook = ''