nostr_terminal/src/editor.c

#include "editor.h"

#include "tui.h"

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

static int editor_write_all(int fd, const char *data, size_t len) {
    size_t off = 0;

    while (off < len) {
        ssize_t n = write(fd, data + off, len - off);
        if (n < 0) {
            if (errno == EINTR) {
                continue;
            }
            return -1;
        }
        off += (size_t)n;
    }

    return 0;
}

static char *editor_read_file_malloc(const char *path) {
    FILE *fp;
    long sz;
    char *buf;
    size_t nread;

    if (!path) {
        return NULL;
    }

    fp = fopen(path, "rb");
    if (!fp) {
        return NULL;
    }

    if (fseek(fp, 0, SEEK_END) != 0) {
        fclose(fp);
        return NULL;
    }

    sz = ftell(fp);
    if (sz <= 0) {
        fclose(fp);
        return NULL;
    }

    if (fseek(fp, 0, SEEK_SET) != 0) {
        fclose(fp);
        return NULL;
    }

    buf = (char *)malloc((size_t)sz + 1U);
    if (!buf) {
        fclose(fp);
        return NULL;
    }

    nread = fread(buf, 1U, (size_t)sz, fp);
    fclose(fp);
    if (nread != (size_t)sz) {
        free(buf);
        return NULL;
    }

    buf[nread] = '\0';
    return buf;
}

typedef struct {
    const char *tmp_path;
    const char *editor_env;
} editor_spawn_ctx_t;

static int editor_spawn(void *user) {
    editor_spawn_ctx_t *ctx = (editor_spawn_ctx_t *)user;
    const char *tmp_path;
    const char *editor_env;
    pid_t pid;
    int status = 0;

    if (!ctx || !ctx->tmp_path) {
        return -1;
    }

    tmp_path = ctx->tmp_path;
    editor_env = ctx->editor_env;

    pid = fork();
    if (pid < 0) {
        return -1;
    }

    if (pid == 0) {
        if (editor_env && editor_env[0] != '\0') {
            char command[2048];
            char *argv_sh[4];

            if (snprintf(command, sizeof(command), "%s \"%s\"", editor_env, tmp_path) >= (int)sizeof(command)) {
                _exit(127);
            }

            argv_sh[0] = "sh";
            argv_sh[1] = "-c";
            argv_sh[2] = command;
            argv_sh[3] = NULL;
            execvp("sh", argv_sh);
            _exit(127);
        }

        {
            char command[4096];
            char *argv_sh[4];

            if (snprintf(command,
                         sizeof(command),
                         "vipe < \"%s\" > \"%s.out\" && mv \"%s.out\" \"%s\"",
                         tmp_path,
                         tmp_path,
                         tmp_path,
                         tmp_path) >= (int)sizeof(command)) {
                _exit(127);
            }

            argv_sh[0] = "sh";
            argv_sh[1] = "-c";
            argv_sh[2] = command;
            argv_sh[3] = NULL;
            execvp("sh", argv_sh);
        }

        {
            char *argv_vi[3];
            argv_vi[0] = "vi";
            argv_vi[1] = (char *)tmp_path;
            argv_vi[2] = NULL;
            execvp("vi", argv_vi);
        }

        _exit(127);
    }

    while (waitpid(pid, &status, 0) < 0) {
        if (errno != EINTR) {
            break;
        }
    }

    if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
        return -1;
    }

    return 0;
}

static int editor_run_command(const char *tmp_path, const char *editor_env) {
    editor_spawn_ctx_t ctx;

    if (!tmp_path) {
        return -1;
    }

    ctx.tmp_path = tmp_path;
    ctx.editor_env = editor_env;
    return nt_run_external_editor(editor_spawn, &ctx);
}

char *editor_launch(const char *initial_content) {
    char template_path[] = "/tmp/nt_editor_XXXXXX";
    int fd;
    char *out = NULL;
    const char *editor_env;

    fd = mkstemp(template_path);
    if (fd < 0) {
        return NULL;
    }

    if (initial_content && initial_content[0] != '\0') {
        size_t len = strlen(initial_content);
        if (editor_write_all(fd, initial_content, len) != 0) {
            close(fd);
            unlink(template_path);
            return NULL;
        }
    }

    if (close(fd) != 0) {
        unlink(template_path);
        return NULL;
    }

    editor_env = getenv("EDITOR");
    if (editor_run_command(template_path, editor_env) != 0) {
        unlink(template_path);
        return NULL;
    }

    out = editor_read_file_malloc(template_path);
    unlink(template_path);
    return out;
}