make nix detection faster

src/detection/packages/packages.h

@@ -1,10 +1,10 @@
 #pragma once
 
+#include "common/processing.h"
 #include "fastfetch.h"
 #include "modules/packages/option.h"
 
-typedef struct FFPackagesResult
-{
+typedef struct FFPackagesResult {
     uint32_t amSystem;
     uint32_t amUser;
     uint32_t apk;
@@ -47,7 +47,7 @@ typedef struct FFPackagesResult
     uint32_t winget;
     uint32_t xbps;
 
-    uint32_t all; //Make sure this goes last
+    uint32_t all; // Make sure this goes last
 
     FFstrbuf pacmanBranch;
 } FFPackagesResult;
@@ -57,7 +57,17 @@ bool ffPackagesReadCache(FFstrbuf* cacheDir, FFstrbuf* cacheContent, const char*
 bool ffPackagesWriteCache(FFstrbuf* cacheDir, FFstrbuf* cacheContent, uint32_t num_elements);
 
 #if defined(__linux__) || defined(__APPLE__) || defined(__GNU__)
+void getNixPackagesMultiImpl(char* paths[], uint32_t counts[], FFProcessHandle handle[], uint8_t length);
 uint32_t ffPackagesGetNix(FFstrbuf* baseDir, const char* dirname);
+#define ffPackagesGetNixMulti(dirs, counts, N)                \
+    do {                                                      \
+        FFProcessHandle _handles[N];                          \
+        char* _paths[N];                                      \
+        for (uint8_t i = 0; i < N; i++) {                     \
+            _paths[i] = dirs[i]->chars;                       \
+        }                                                     \
+        getNixPackagesMultiImpl(_paths, counts, _handles, N); \
+    } while (0)
 #endif
 #ifndef _WIN32
 uint32_t ffPackagesGetNumElements(const char* dirname, bool isdir);

src/detection/packages/packages_apple.c

@@ -2,7 +2,9 @@
 #include "common/io/io.h"
 #include "common/parsing.h"
 #include "common/processing.h"
+#include "util/FFstrbuf.h"
 #include "util/stringUtils.h"
+#include <stdint.h>
 
 static void countBrewPackages(FFstrbuf* baseDir, FFPackagesResult* result)
 {
@@ -61,9 +63,19 @@ void ffDetectPackagesImpl(FFPackagesResult* result, FFPackagesOptions* options)
     if (!(options->disabled & FF_PACKAGES_FLAG_NIX_BIT))
     {
         ffStrbufSetS(&baseDir, FASTFETCH_TARGET_DIR_ROOT);
-        result->nixDefault += ffPackagesGetNix(&baseDir, "/nix/var/nix/profiles/default");
-        result->nixSystem += ffPackagesGetNix(&baseDir, "/run/current-system");
-        ffStrbufSet(&baseDir, &instance.state.platform.homeDir);
-        result->nixUser = ffPackagesGetNix(&baseDir, "/.nix-profile");
+        ffStrbufAppendS(&baseDir, "/nix/var/nix/profiles/default");
+
+        FF_STRBUF_AUTO_DESTROY dir2 = ffStrbufCreateS(FASTFETCH_TARGET_DIR_ROOT);
+        ffStrbufAppendS(&dir2, "/run/current-system");
+
+        FF_STRBUF_AUTO_DESTROY dir3 = ffStrbufCreateCopy(&instance.state.platform.homeDir);
+        ffStrbufAppendS(&dir3, "/.nix-profile");
+
+        FFstrbuf* dirs[] = {&baseDir, &dir2, &dir3};
+        uint32_t counts[3] = {0};
+        ffPackagesGetNixMulti(dirs, counts, 3);
+        result->nixDefault = counts[0];
+        result->nixSystem = counts[1];
+        result->nixUser = counts[2];
     }
 }

src/detection/packages/packages_nix.c

@@ -2,6 +2,7 @@
 #include "common/io/io.h"
 #include "common/processing.h"
 #include "util/stringUtils.h"
+#include <stdint.h>
 
 static bool isValidNixPkg(FFstrbuf* pkg)
 {
@@ -51,6 +52,53 @@ static bool isValidNixPkg(FFstrbuf* pkg)
     return state == MATCH;
 }
 
+void getNixPackagesMultiImpl(char* paths[], uint32_t counts[], FFProcessHandle handle[], uint8_t length)
+{
+    //Implementation based on bash script from here:
+    //https://github.com/fastfetch-cli/fastfetch/issues/195#issuecomment-1191748222
+    // no need to use hash, it is not faster
+    for (uint8_t i = 0; i < length; i++){
+        handle[i].pid = 0;
+        //  Nix detection is kinda slow, so we only do it if the dir exists
+        if(ffPathExists(paths[i], FF_PATHTYPE_DIRECTORY)){
+            ffProcessSpawn((char* const[]) {
+                "nix-store",
+                "--query",
+                "--requisites",
+                paths[i],
+                NULL
+            }, false, &handle[i]);
+        }
+    }
+    for (uint8_t i = 0; i < length; i++){
+        FF_STRBUF_AUTO_DESTROY output = ffStrbufCreateA(1024);
+        if (!handle[i].pid){
+            counts[i] = 0;
+            continue;
+        }
+        ffProcessReadOutput(&handle[i], &output);
+        uint32_t lineLength = 0;
+        for (uint32_t j = 0; j < output.length; j++)
+        {
+            if (output.chars[j] != '\n')
+            {
+                lineLength++;
+                continue;
+            }
+
+            output.chars[j] = '\0';
+            FFstrbuf line = {
+                .allocated = 0,
+                .length = lineLength,
+                .chars = output.chars + j - lineLength
+            };
+            if (isValidNixPkg(&line))
+                counts[i] += 1;
+            lineLength = 0;
+        }
+    }
+}
+
 static bool checkNixCache(FFstrbuf* cacheDir, FFstrbuf* hash, uint32_t* count)
 {
     if (!ffPathExists(cacheDir->chars, FF_PATHTYPE_FILE))