app : introduce the llama unified executable (#23296)

* app : introduce the llama unified executable

Signed-off-by: Adrien Gallouët <angt@huggingface.co>

* Use serve for server

Signed-off-by: Adrien Gallouët <angt@huggingface.co>

* Hide completion and bench, add help command

Signed-off-by: Adrien Gallouët <angt@huggingface.co>

* Remove STATIC

Signed-off-by: Adrien Gallouët <angt@huggingface.co>

* Use -impl targets instead of -lib

Signed-off-by: Adrien Gallouët <angt@huggingface.co>

* Revert "Remove STATIC"

This reverts commit cc44caccb9902b34a3531633edac911e5b3d65cd.

---------

Signed-off-by: Adrien Gallouët <angt@huggingface.co>

app/llama.cpp

@@ -0,0 +1,67 @@
+#include <cstdio>
+#include <string>
+#include <vector>
+
+int llama_server(int argc, char ** argv);
+int llama_cli(int argc, char ** argv);
+
+// hidden
+int llama_completion(int argc, char ** argv);
+int llama_bench(int argc, char ** argv);
+static int help(int argc, char ** argv);
+
+struct command {
+    const char * name;
+    const char * desc;
+    std::vector<std::string> aliases;
+    bool hidden;
+    int (*func)(int, char **);
+};
+
+static const command cmds[] = {
+    {"serve",      "HTTP API server",                    {"server"},   false, llama_server     },
+    {"cli",        "Command-line interactive interface", {"client"},   false, llama_cli        },
+    {"completion", "Text completion",                    {"complete"}, true,  llama_completion },
+    {"bench",      "Benchmarking tool",                  {},           true,  llama_bench      },
+    {"help",       "Show available commands",            {},           true,  help             },
+};
+
+static int help(int argc, char ** argv) {
+    const bool show_all = argc >= 2 && std::string(argv[1]) == "all";
+
+    printf("Usage: llama <command> [options]\n\nAvailable commands:\n");
+
+    for (const auto & cmd : cmds) {
+        if (show_all || !cmd.hidden) {
+            printf("  %-15s %s\n", cmd.name, cmd.desc);
+        }
+    }
+    printf("\nRun 'llama <command> --help' for command-specific usage.\n");
+
+    return 0;
+}
+
+static bool matches(const std::string & arg, const command & cmd) {
+    if (arg == cmd.name) {
+        return true;
+    }
+    for (const auto & alias : cmd.aliases) {
+        if (arg == alias) {
+            return true;
+        }
+    }
+    return false;
+}
+
+int main(int argc, char ** argv) {
+    const std::string arg = argc >= 2 ? argv[1] : "help";
+
+    for (const auto & cmd : cmds) {
+        if (matches(arg, cmd)) {
+            return cmd.func(argc - 1, argv + 1);
+        }
+    }
+
+    fprintf(stderr, "error: unknown command '%s'\n", arg.c_str());
+    return 1;
+}