feat(stablediffusion-ggml): add lora support (#7542)

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

backend/go/stablediffusion-ggml/gosd.cpp

@@ -8,7 +8,9 @@
 #include <time.h>
 #include <string>
 #include <vector>
+#include <map>
 #include <filesystem>
+#include <algorithm>
 #include "gosd.h"
 
 #define STB_IMAGE_IMPLEMENTATION
@@ -23,6 +25,7 @@
 #define STB_IMAGE_RESIZE_STATIC
 #include "stb_image_resize.h"
 #include <stdlib.h>
+#include <regex>
 
 // Names of the sampler method, same order as enum sample_method in stable-diffusion.h
 const char* sample_method_str[] = {
@@ -133,6 +136,13 @@ static std::vector<sd_embedding_t> embedding_vec;
 // Storage for embedding strings (needs to persist as long as embedding_vec references them)
 static std::vector<std::string> embedding_strings;
 
+// Storage for LoRAs (needs to persist for the lifetime of generation params)
+static std::vector<sd_lora_t> lora_vec;
+// Storage for LoRA strings (needs to persist as long as lora_vec references them)
+static std::vector<std::string> lora_strings;
+// Storage for lora_dir path
+static std::string lora_dir_path;
+
 // Build embeddings vector from directory, similar to upstream CLI
 static void build_embedding_vec(const char* embedding_dir) {
     embedding_vec.clear();
@@ -186,6 +196,229 @@ static void build_embedding_vec(const char* embedding_dir) {
     fprintf(stderr, "Loaded %zu embeddings from %s\n", embedding_vec.size(), embedding_dir);
 }
 
+// Discover LoRA files in directory and build a map of name -> path
+static std::map<std::string, std::string> discover_lora_files(const char* lora_dir) {
+    std::map<std::string, std::string> lora_map;
+    
+    if (!lora_dir || strlen(lora_dir) == 0) {
+        fprintf(stderr, "LoRA directory not specified\n");
+        return lora_map;
+    }
+    
+    if (!std::filesystem::exists(lora_dir) || !std::filesystem::is_directory(lora_dir)) {
+        fprintf(stderr, "LoRA directory does not exist or is not a directory: %s\n", lora_dir);
+        return lora_map;
+    }
+    
+    static const std::vector<std::string> valid_ext = {".safetensors", ".ckpt", ".pt", ".gguf"};
+    
+    fprintf(stderr, "Discovering LoRA files in: %s\n", lora_dir);
+    
+    for (const auto& entry : std::filesystem::directory_iterator(lora_dir)) {
+        if (!entry.is_regular_file()) {
+            continue;
+        }
+        
+        auto path = entry.path();
+        std::string ext = path.extension().string();
+        
+        bool valid = false;
+        for (const auto& e : valid_ext) {
+            if (ext == e) {
+                valid = true;
+                break;
+            }
+        }
+        if (!valid) {
+            continue;
+        }
+        
+        std::string name = path.stem().string();  // stem() already removes extension
+        std::string full_path = path.string();
+        
+        // Store the name (without extension) -> full path mapping
+        // This allows users to specify just the name in <lora:name:strength>
+        lora_map[name] = full_path;
+        
+        fprintf(stderr, "Found LoRA file: %s -> %s\n", name.c_str(), full_path.c_str());
+    }
+    
+    fprintf(stderr, "Discovered %zu LoRA files in %s\n", lora_map.size(), lora_dir);
+    return lora_map;
+}
+
+// Helper function to check if a path is absolute (matches upstream)
+static bool is_absolute_path(const std::string& p) {
+#ifdef _WIN32
+    // Windows: C:/path or C:\path
+    return p.size() > 1 && std::isalpha(static_cast<unsigned char>(p[0])) && p[1] == ':';
+#else
+    // Unix: /path
+    return !p.empty() && p[0] == '/';
+#endif
+}
+
+// Parse LoRAs from prompt string (e.g., "<lora:name:1.0>" or "<lora:name>")
+// Returns a vector of LoRA info and the cleaned prompt with LoRA tags removed
+// Matches upstream implementation more closely
+static std::pair<std::vector<sd_lora_t>, std::string> parse_loras_from_prompt(const std::string& prompt, const char* lora_dir) {
+    std::vector<sd_lora_t> loras;
+    std::string cleaned_prompt = prompt;
+    
+    if (!lora_dir || strlen(lora_dir) == 0) {
+        fprintf(stderr, "LoRA directory not set, cannot parse LoRAs from prompt\n");
+        return {loras, cleaned_prompt};
+    }
+    
+    // Discover LoRA files for name-based lookup
+    std::map<std::string, std::string> discovered_lora_map = discover_lora_files(lora_dir);
+    
+    // Map to accumulate multipliers for the same LoRA (matches upstream)
+    std::map<std::string, float> lora_map;
+    std::map<std::string, float> high_noise_lora_map;
+    
+    static const std::regex re(R"(<lora:([^:>]+):([^>]+)>)");
+    static const std::vector<std::string> valid_ext = {".pt", ".safetensors", ".gguf"};
+    std::smatch m;
+    
+    std::string tmp = prompt;
+    
+    fprintf(stderr, "Parsing LoRAs from prompt: %s\n", prompt.c_str());
+    
+    while (std::regex_search(tmp, m, re)) {
+        std::string raw_path = m[1].str();
+        const std::string raw_mul = m[2].str();
+        
+        float mul = 0.f;
+        try {
+            mul = std::stof(raw_mul);
+        } catch (...) {
+            tmp = m.suffix().str();
+            cleaned_prompt = std::regex_replace(cleaned_prompt, re, "", std::regex_constants::format_first_only);
+            fprintf(stderr, "Invalid LoRA multiplier '%s', skipping\n", raw_mul.c_str());
+            continue;
+        }
+        
+        bool is_high_noise = false;
+        static const std::string prefix = "|high_noise|";
+        if (raw_path.rfind(prefix, 0) == 0) {
+            raw_path.erase(0, prefix.size());
+            is_high_noise = true;
+        }
+        
+        std::filesystem::path final_path;
+        if (is_absolute_path(raw_path)) {
+            final_path = raw_path;
+        } else {
+            // Try name-based lookup first
+            auto it = discovered_lora_map.find(raw_path);
+            if (it != discovered_lora_map.end()) {
+                final_path = it->second;
+            } else {
+                // Try case-insensitive lookup
+                bool found = false;
+                for (const auto& pair : discovered_lora_map) {
+                    std::string lower_name = raw_path;
+                    std::string lower_key = pair.first;
+                    std::transform(lower_name.begin(), lower_name.end(), lower_name.begin(), ::tolower);
+                    std::transform(lower_key.begin(), lower_key.end(), lower_key.begin(), ::tolower);
+                    if (lower_name == lower_key) {
+                        final_path = pair.second;
+                        found = true;
+                        break;
+                    }
+                }
+                if (!found) {
+                    // Try as relative path in lora_dir
+                    final_path = std::filesystem::path(lora_dir) / raw_path;
+                }
+            }
+        }
+        
+        // Try adding extensions if file doesn't exist
+        if (!std::filesystem::exists(final_path)) {
+            bool found = false;
+            for (const auto& ext : valid_ext) {
+                std::filesystem::path try_path = final_path;
+                try_path += ext;
+                if (std::filesystem::exists(try_path)) {
+                    final_path = try_path;
+                    found = true;
+                    break;
+                }
+            }
+            if (!found) {
+                fprintf(stderr, "WARNING: LoRA file not found: %s\n", final_path.lexically_normal().string().c_str());
+                tmp = m.suffix().str();
+                cleaned_prompt = std::regex_replace(cleaned_prompt, re, "", std::regex_constants::format_first_only);
+                continue;
+            }
+        }
+        
+        // Normalize path (matches upstream)
+        const std::string key = final_path.lexically_normal().string();
+        
+        // Accumulate multiplier if same LoRA appears multiple times (matches upstream)
+        if (is_high_noise) {
+            high_noise_lora_map[key] += mul;
+        } else {
+            lora_map[key] += mul;
+        }
+        
+        fprintf(stderr, "Parsed LoRA: path='%s', multiplier=%.2f, is_high_noise=%s\n", 
+                key.c_str(), mul, is_high_noise ? "true" : "false");
+        
+        cleaned_prompt = std::regex_replace(cleaned_prompt, re, "", std::regex_constants::format_first_only);
+        tmp = m.suffix().str();
+    }
+    
+    // Build final LoRA vector from accumulated maps (matches upstream)
+    // Store all path strings first to ensure they persist
+    for (const auto& kv : lora_map) {
+        lora_strings.push_back(kv.first);
+    }
+    for (const auto& kv : high_noise_lora_map) {
+        lora_strings.push_back(kv.first);
+    }
+    
+    // Now build the LoRA vector with pointers to the stored strings
+    size_t string_idx = 0;
+    for (const auto& kv : lora_map) {
+        sd_lora_t item;
+        item.is_high_noise = false;
+        item.path = lora_strings[string_idx].c_str();
+        item.multiplier = kv.second;
+        loras.push_back(item);
+        string_idx++;
+    }
+    
+    for (const auto& kv : high_noise_lora_map) {
+        sd_lora_t item;
+        item.is_high_noise = true;
+        item.path = lora_strings[string_idx].c_str();
+        item.multiplier = kv.second;
+        loras.push_back(item);
+        string_idx++;
+    }
+    
+    // Clean up extra spaces
+    std::regex space_regex(R"(\s+)");
+    cleaned_prompt = std::regex_replace(cleaned_prompt, space_regex, " ");
+    // Trim leading/trailing spaces
+    size_t first = cleaned_prompt.find_first_not_of(" \t");
+    if (first != std::string::npos) {
+        cleaned_prompt.erase(0, first);
+    }
+    size_t last = cleaned_prompt.find_last_not_of(" \t");
+    if (last != std::string::npos) {
+        cleaned_prompt.erase(last + 1);
+    }
+    
+    fprintf(stderr, "Parsed %zu LoRA(s) from prompt. Cleaned prompt: %s\n", loras.size(), cleaned_prompt.c_str());
+    
+    return {loras, cleaned_prompt};
+}
+
 // Copied from the upstream CLI
 static void sd_log_cb(enum sd_log_level_t level, const char* log, void* data) {
     //SDParams* params = (SDParams*)data;
@@ -304,11 +537,17 @@ int load_model(const char *model, char *model_path, char* options[], int threads
                 std::filesystem::path lora_path(optval);
                 std::filesystem::path full_lora_path = model_path_str / lora_path;
                 lora_dir = strdup(full_lora_path.string().c_str());
-                fprintf(stderr, "Lora dir resolved to: %s\n", lora_dir);
+                lora_dir_path = full_lora_path.string();
+                fprintf(stderr, "LoRA dir resolved to: %s\n", lora_dir);
             } else {
                 lora_dir = strdup(optval);
+                lora_dir_path = std::string(optval);
                 fprintf(stderr, "No model path provided, using lora dir as-is: %s\n", lora_dir);
             }
+            // Discover LoRAs immediately when directory is set
+            if (lora_dir && strlen(lora_dir) > 0) {
+                discover_lora_files(lora_dir);
+            }
         }
 
         // New parsing
@@ -450,6 +689,14 @@ int load_model(const char *model, char *model_path, char* options[], int threads
     ctx_params.taesd_path = taesd_path;
     ctx_params.control_net_path = control_net_path;
     ctx_params.lora_model_dir = lora_dir;
+    if (lora_dir && strlen(lora_dir) > 0) {
+        lora_dir_path = std::string(lora_dir);
+        fprintf(stderr, "LoRA model directory set to: %s\n", lora_dir);
+        // Discover LoRAs at load time for logging
+        discover_lora_files(lora_dir);
+    } else {
+        fprintf(stderr, "WARNING: LoRA model directory not set. LoRAs in prompts will not be loaded.\n");
+    }
     // Set embeddings array and count
     ctx_params.embeddings = embedding_vec.empty() ? NULL : embedding_vec.data();
     ctx_params.embedding_count = static_cast<uint32_t>(embedding_vec.size());
@@ -546,9 +793,63 @@ sd_img_gen_params_t* sd_img_gen_params_new(void) {
     return params;
 }
 
+// Storage for cleaned prompt strings (needs to persist)
+static std::string cleaned_prompt_storage;
+static std::string cleaned_negative_prompt_storage;
+
 void sd_img_gen_params_set_prompts(sd_img_gen_params_t *params, const char *prompt, const char *negative_prompt) {
-    params->prompt = prompt;
-    params->negative_prompt = negative_prompt;
+    // Clear previous LoRA data
+    lora_vec.clear();
+    lora_strings.clear();
+    
+    // Parse LoRAs from prompt
+    std::string prompt_str = prompt ? prompt : "";
+    std::string negative_prompt_str = negative_prompt ? negative_prompt : "";
+    
+    // Get lora_dir from ctx_params if available, otherwise use stored path
+    const char* lora_dir_to_use = ctx_params.lora_model_dir;
+    if (!lora_dir_to_use || strlen(lora_dir_to_use) == 0) {
+        lora_dir_to_use = lora_dir_path.empty() ? nullptr : lora_dir_path.c_str();
+    }
+    
+    auto [loras, cleaned_prompt] = parse_loras_from_prompt(prompt_str, lora_dir_to_use);
+    lora_vec = loras;
+    cleaned_prompt_storage = cleaned_prompt;
+    
+    // Also check negative prompt for LoRAs (though this is less common)
+    auto [neg_loras, cleaned_negative] = parse_loras_from_prompt(negative_prompt_str, lora_dir_to_use);
+    // Merge negative prompt LoRAs (though typically not used)
+    if (!neg_loras.empty()) {
+        fprintf(stderr, "Note: Found %zu LoRAs in negative prompt (may not be supported)\n", neg_loras.size());
+    }
+    cleaned_negative_prompt_storage = cleaned_negative;
+    
+    // Set the cleaned prompts
+    params->prompt = cleaned_prompt_storage.c_str();
+    params->negative_prompt = cleaned_negative_prompt_storage.c_str();
+    
+    // Set LoRAs in params
+    params->loras = lora_vec.empty() ? nullptr : lora_vec.data();
+    params->lora_count = static_cast<uint32_t>(lora_vec.size());
+    
+    fprintf(stderr, "Set prompts with %zu LoRAs. Original prompt: %s\n", lora_vec.size(), prompt ? prompt : "(null)");
+    fprintf(stderr, "Cleaned prompt: %s\n", cleaned_prompt_storage.c_str());
+    
+    // Debug: Verify LoRAs are set correctly
+    if (params->loras && params->lora_count > 0) {
+        fprintf(stderr, "DEBUG: LoRAs set in params structure:\n");
+        for (uint32_t i = 0; i < params->lora_count; i++) {
+            fprintf(stderr, "  params->loras[%u]: path='%s' (ptr=%p), multiplier=%.2f, is_high_noise=%s\n",
+                    i,
+                    params->loras[i].path ? params->loras[i].path : "(null)",
+                    (void*)params->loras[i].path,
+                    params->loras[i].multiplier,
+                    params->loras[i].is_high_noise ? "true" : "false");
+        }
+    } else {
+        fprintf(stderr, "DEBUG: No LoRAs set in params structure (loras=%p, lora_count=%u)\n",
+                (void*)params->loras, params->lora_count);
+    }
 }
 
 void sd_img_gen_params_set_dimensions(sd_img_gen_params_t *params, int width, int height) {
@@ -740,6 +1041,20 @@ int gen_image(sd_img_gen_params_t *p, int steps, char *dst, float cfg_scale, cha
         }
     }
 
+    // Log LoRA information
+    if (p->loras && p->lora_count > 0) {
+        fprintf(stderr, "Using %u LoRA(s) in generation:\n", p->lora_count);
+        for (uint32_t i = 0; i < p->lora_count; i++) {
+            fprintf(stderr, "  LoRA[%u]: path='%s', multiplier=%.2f, is_high_noise=%s\n",
+                    i, 
+                    p->loras[i].path ? p->loras[i].path : "(null)",
+                    p->loras[i].multiplier,
+                    p->loras[i].is_high_noise ? "true" : "false");
+        }
+    } else {
+        fprintf(stderr, "No LoRAs specified for this generation\n");
+    }
+
     fprintf(stderr, "Generating image with params: \nctx\n---\n%s\ngen\n---\n%s\n",
             sd_ctx_params_to_str(&ctx_params),
             sd_img_gen_params_to_str(p));
@@ -802,3 +1117,4 @@ int unload() {
     free_sd_ctx(sd_c);
     return 0;
 }
+