CST-agent/tests/test_attach.c

#define _POSIX_C_SOURCE 200809L

#include "cJSON.h"
#include "cst_attach.h"
#include "cst_agent.h"
#include "cst_clipboard.h"
#include "cst_test_util.h"
#include "os_compat.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static int nfail;

#define EXPECT(cond, msg)                                                      \
  do {                                                                         \
    if (!(cond)) {                                                             \
      fprintf(stderr, "FAIL %s:%d: %s\n", __FILE__, __LINE__, msg);            \
      nfail++;                                                                 \
    }                                                                          \
  } while (0)

static void put_be32(unsigned char *p, unsigned v) {
  p[0] = (unsigned char)(v >> 24);
  p[1] = (unsigned char)(v >> 16);
  p[2] = (unsigned char)(v >> 8);
  p[3] = (unsigned char)v;
}

static void put_le16(unsigned char *p, unsigned v) {
  p[0] = (unsigned char)(v & 0xFF);
  p[1] = (unsigned char)((v >> 8) & 0xFF);
}

/* 8 signature + 4 length + "IHDR" + w + h (what cst_attach_dimensions reads). */
static size_t png_hdr(unsigned char *b, unsigned w, unsigned h) {
  static const unsigned char sig[8] = {0x89, 'P', 'N', 'G', '\r', '\n', 0x1A, '\n'};
  memcpy(b, sig, 8);
  b[8] = b[9] = b[10] = 0;
  b[11] = 13;
  memcpy(b + 12, "IHDR", 4);
  put_be32(b + 16, w);
  put_be32(b + 20, h);
  return 32;
}

static size_t gif_hdr(unsigned char *b, unsigned w, unsigned h) {
  memcpy(b, "GIF89a", 6);
  put_le16(b + 6, w);
  put_le16(b + 8, h);
  return 16;
}

static void put_le32(unsigned char *p, unsigned v) {
  p[0] = (unsigned char)(v & 0xFF);
  p[1] = (unsigned char)((v >> 8) & 0xFF);
  p[2] = (unsigned char)((v >> 16) & 0xFF);
  p[3] = (unsigned char)((v >> 24) & 0xFF);
}

static size_t bmp_hdr(unsigned char *b, int w, int h) {
  memset(b, 0, 64);
  b[0] = 'B';
  b[1] = 'M';
  put_le32(b + 18, (unsigned)w);
  put_le32(b + 22, (unsigned)h);
  return 64;
}

/* FFD8 + a filler APP0 segment + SOF0 carrying the frame size. */
static size_t jpeg_hdr(unsigned char *b, unsigned w, unsigned h) {
  size_t i = 0;
  b[i++] = 0xFF;
  b[i++] = 0xD8;
  b[i++] = 0xFF;
  b[i++] = 0xE0;
  b[i++] = 0x00;
  b[i++] = 0x04;
  b[i++] = 0x00;
  b[i++] = 0x00;
  b[i++] = 0xFF;
  b[i++] = 0xC0;
  b[i++] = 0x00;
  b[i++] = 0x0B;
  b[i++] = 0x08;
  b[i++] = (unsigned char)(h >> 8);
  b[i++] = (unsigned char)h;
  b[i++] = (unsigned char)(w >> 8);
  b[i++] = (unsigned char)w;
  b[i++] = 0x01; /* one component */
  b[i++] = 0x01; /* component id */
  b[i++] = 0x11; /* sampling */
  b[i++] = 0x00; /* quant table */
  return i;
}

static void test_sniff(void) {
  unsigned char b[64];
  char mime[32];
  size_t n;

  n = png_hdr(b, 32, 24);
  EXPECT(cst_attach_sniff(b, n, mime, sizeof(mime)) == 0 &&
             strcmp(mime, "image/png") == 0, "PNG sniffed");
  n = jpeg_hdr(b, 20, 10);
  EXPECT(cst_attach_sniff(b, n, mime, sizeof(mime)) == 0 &&
             strcmp(mime, "image/jpeg") == 0, "JPEG sniffed");
  n = gif_hdr(b, 3, 5);
  EXPECT(cst_attach_sniff(b, n, mime, sizeof(mime)) == 0 &&
             strcmp(mime, "image/gif") == 0, "GIF sniffed");
  memcpy(b, "RIFF\0\0\0\0WEBPVP8 ", 16);
  EXPECT(cst_attach_sniff(b, 30, mime, sizeof(mime)) == 0 &&
             strcmp(mime, "image/webp") == 0, "WebP sniffed");
  n = bmp_hdr(b, 7, 9);
  EXPECT(cst_attach_sniff(b, n, mime, sizeof(mime)) == 0 &&
             strcmp(mime, "image/bmp") == 0, "BMP sniffed");

  /* an extension never decides: text and a PDF are not images */
  EXPECT(cst_attach_sniff("hello, world", 12, mime, sizeof(mime)) != 0,
         "text rejected");
  EXPECT(cst_attach_sniff("%PDF-1.7\n", 9, mime, sizeof(mime)) != 0,
         "PDF rejected");
  EXPECT(cst_attach_sniff("\x89PNG", 4, mime, sizeof(mime)) != 0,
         "truncated PNG rejected");
  EXPECT(cst_attach_sniff("", 0, mime, sizeof(mime)) != 0, "empty rejected");
}

static void test_dimensions(void) {
  unsigned char b[64];
  int w = 0, h = 0;
  size_t n;

  n = png_hdr(b, 1280, 720);
  EXPECT(cst_attach_dimensions(b, n, &w, &h) == 0 && w == 1280 && h == 720,
         "PNG dimensions");
  n = gif_hdr(b, 16, 40);
  EXPECT(cst_attach_dimensions(b, n, &w, &h) == 0 && w == 16 && h == 40,
         "GIF dimensions");
  n = bmp_hdr(b, 7, 9);
  EXPECT(cst_attach_dimensions(b, n, &w, &h) == 0 && w == 7 && h == 9,
         "BMP dimensions");
  n = jpeg_hdr(b, 640, 480);
  EXPECT(cst_attach_dimensions(b, n, &w, &h) == 0 && w == 640 && h == 480,
         "JPEG dimensions");

  w = h = -1;
  EXPECT(cst_attach_dimensions("nope", 4, &w, &h) != 0 && w == 0 && h == 0,
         "unknown format gives 0x0");
}

static void test_base64(void) {
  char *s = cst_base64_encode("Man", 3);
  EXPECT(s && strcmp(s, "TWFu") == 0, "base64 <Man>");
  free(s);
  s = cst_base64_encode("Ma", 2);
  EXPECT(s && strcmp(s, "TWE=") == 0, "base64 padding 1");
  free(s);
  s = cst_base64_encode("M", 1);
  EXPECT(s && strcmp(s, "TQ==") == 0, "base64 padding 2");
  free(s);
  s = cst_base64_encode("\x00\xff\xfe", 3);
  EXPECT(s && strcmp(s, "AP/+") == 0, "base64 binary");
  free(s);

  size_t n = 0;
  char *d = cst_base64_decode("TWFu", 4, &n);
  EXPECT(d && n == 3 && memcmp(d, "Man", 3) == 0, "decode <Man>");
  free(d);
  d = cst_base64_decode("TQ==", 4, &n);
  EXPECT(d && n == 1 && d[0] == 'M', "decode with padding");
  free(d);
  d = cst_base64_decode("AP/+\n", 5, &n);
  EXPECT(d && n == 3 && memcmp(d, "\x00\xff\xfe", 3) == 0,
         "decode binary, newline ignored");
  free(d);
  d = cst_base64_decode("AP_-", 4, &n);
  EXPECT(d && n == 3 && memcmp(d, "\x00\xff\xfe", 3) == 0, "URL-safe alphabet");
  free(d);
  EXPECT(cst_base64_decode("A*B=", 4, &n) == NULL, "bad character refused");

  unsigned char raw[200];
  for (int i = 0; i < 200; i++)
    raw[i] = (unsigned char)(i * 37);
  for (size_t len = 0; len < 7; len++) {
    char *e = cst_base64_encode(raw, 190 + len);
    d = e ? cst_base64_decode(e, strlen(e), &n) : NULL;
    EXPECT(d && n == 190 + len && memcmp(d, raw, n) == 0, "round trip");
    free(e);
    free(d);
  }
}

static void test_rel_ok(const char *root) {
  EXPECT(cst_attach_rel_ok("img-0a1b2c3d.png"), "normal name accepted");
  EXPECT(!cst_attach_rel_ok("../x.png"), "parent dir refused");
  EXPECT(!cst_attach_rel_ok("a/../../b.png"), "slash refused");
  EXPECT(!cst_attach_rel_ok("/etc/passwd"), "absolute refused");
  EXPECT(!cst_attach_rel_ok("a\\b.png"), "backslash refused");
  EXPECT(!cst_attach_rel_ok(".hidden"), "dot file refused");
  EXPECT(!cst_attach_rel_ok(""), "empty refused");

  cJSON *arr = cJSON_Parse("[{\"id\":\"x\",\"rel\":\"../../secret.png\"},"
                           "{\"id\":\"y\",\"rel\":\"img-1.png\"}]");
  int n = 0;
  cst_attachment_t *back = cst_attachments_from_json(arr, &n);
  EXPECT(n == 1 && back && strcmp(back[0].id, "y") == 0,
         "escaping rel dropped on load");
  cst_attachments_free(back, n);
  cJSON_Delete(arr);

  /* a stored file swapped for non-image bytes is not sent */
  char session[1024], full[1024], err[256];
  snprintf(session, sizeof(session), "%.900s/sessions/r.jsonl", root);
  unsigned char b[64];
  size_t bn = png_hdr(b, 4, 4);
  cst_attachment_t *a =
      cst_attach_import_bytes(session, "x.png", (const char *)b, bn, err,
                              sizeof(err));
  EXPECT(a != NULL, "stored");
  if (!a)
    return;
  EXPECT(cst_attach_full_path(session, a, full, sizeof(full)) == 0, "path");
  FILE *f = fopen(full, "wb");
  if (f) {
    fputs("plain text now", f);
    fclose(f);
  }
  size_t rn = 0;
  EXPECT(cst_attach_read(session, a, &rn, err, sizeof(err)) == NULL &&
             strstr(err, "no longer an image"),
         "read re-checks the bytes");
  EXPECT(cst_attach_data_url(session, a) == NULL, "no data url for it");
  snprintf(a->rel, sizeof(a->rel), "../r.jsonl");
  EXPECT(cst_attach_full_path(session, a, full, sizeof(full)) != 0,
         "full path refuses an escaping rel");
  cst_attach_free(a);
}

static void test_store(const char *root) {
  char session[1024], dir[1024];
  snprintf(session, sizeof(session), "%.900s/sessions/a.jsonl", root);
  unsigned char b[64];
  size_t n = png_hdr(b, 32, 24);
  char err[256];

  cst_attachment_t *a = cst_attach_import_bytes(session, "shot.png",
                                                (const char *)b, n, err,
                                                sizeof(err));
  EXPECT(a != NULL, "import stored");
  if (!a) {
    fprintf(stderr, "  err: %s\n", err);
    return;
  }
  EXPECT(strcmp(a->mime, "image/png") == 0, "stored mime");
  EXPECT(a->width == 32 && a->height == 24, "stored dimensions");
  EXPECT(a->bytes == (long long)n, "stored size");
  EXPECT(strcmp(a->name, "shot.png") == 0, "stored name");
  EXPECT(strcmp(a->origin, "user") == 0, "origin=user");
  EXPECT(strcmp(a->rel, "img-") != 0 && strstr(a->rel, ".png") != NULL,
         "rel has a .png extension");

  EXPECT(cst_attach_dir(session, dir, sizeof(dir)) == 0, "attach dir");
  char full[1024];
  EXPECT(cst_attach_full_path(session, a, full, sizeof(full)) == 0 &&
             strstr(full, "attachments/") != NULL,
         "full path inside attachments/");
  FILE *f = fopen(full, "rb");
  EXPECT(f != NULL, "stored file exists");
  if (f)
    fclose(f);

  char desc[128];
  cst_attach_describe(a, desc, sizeof(desc));
  EXPECT(strstr(desc, "32x24") && strstr(desc, "png"), "describe has size");

  size_t rn = 0;
  char *data = cst_attach_read(session, a, &rn, err, sizeof(err));
  EXPECT(data && rn == n && memcmp(data, b, n) == 0, "read back exact bytes");
  free(data);

  char *url = cst_attach_data_url(session, a);
  EXPECT(url && strncmp(url, "data:image/png;base64,", 22) == 0,
         "data url prefix");
  if (url)
    EXPECT(strlen(url) == 22 + ((n + 2) / 3) * 4, "data url length");
  free(url);

  cst_attach_free(a);

  /* a text file named .png is still refused */
  EXPECT(cst_attach_import_bytes(session, "fake.png", "not an image", 12, err,
                                 sizeof(err)) == NULL,
         "content decides, not the name");
  EXPECT(strstr(err, "not a supported image") != NULL, "err explains why");
  EXPECT(cst_attach_import_bytes(session, "empty.png", "", 0, err,
                                 sizeof(err)) == NULL,
         "empty data refused");
}

static void test_import_file(const char *root) {
  char session[1024], src[1024];
  snprintf(session, sizeof(session), "%.900s/sessions/b.jsonl", root);
  snprintf(src, sizeof(src), "%.900s/logo.gif", root);
  unsigned char b[64];
  size_t n = gif_hdr(b, 8, 6);
  FILE *f = fopen(src, "wb");
  EXPECT(f != NULL, "write source image");
  if (f) {
    fwrite(b, 1, n, f);
    fclose(f);
  }
  char err[256];
  cst_attachment_t *a =
      cst_attach_import_file(session, src, err, sizeof(err));
  EXPECT(a != NULL, "file imported");
  if (a) {
    EXPECT(strcmp(a->mime, "image/gif") == 0, "imported mime");
    EXPECT(strcmp(a->name, "logo.gif") == 0, "imported keeps the leaf name");
    EXPECT(a->width == 8 && a->height == 6, "imported dimensions");
    cst_attach_free(a);
  }
  EXPECT(cst_attach_import_file(session, "/nonexistent/x.png", err,
                                sizeof(err)) == NULL,
         "missing file refused");
}

/* Documents: text is stored as text, a PDF as its text layer while the mime
 * still says PDF, and neither is an image as far as the wire is concerned. */
static void test_documents(const char *root) {
  char session[1024], src[1024];
  snprintf(session, sizeof(session), "%.900s/sessions/doc.jsonl", root);
  char err[256] = "";

  const char *text = "# Notes\n\nFive painters, one canvas.\n";
  snprintf(src, sizeof(src), "%.900s/notes.md", root);
  FILE *f = fopen(src, "wb");
  EXPECT(f != NULL, "write the text file");
  if (f) {
    fwrite(text, 1, strlen(text), f);
    fclose(f);
  }
  cst_attachment_t *a = cst_attach_import_file(session, src, err, sizeof(err));
  EXPECT(a != NULL, "text file imported");
  if (a) {
    EXPECT(strcmp(a->mime, "text/plain") == 0, "text mime");
    EXPECT(!cst_attach_is_image(a) && cst_attach_is_text(a), "not an image");
    EXPECT(a->pages == 0, "no pages for text");
    EXPECT(strstr(a->rel, ".txt") != NULL, "text stored as .txt");
    EXPECT(a->bytes == (long long)strlen(text), "text size");
    size_t n = 0;
    char *back = cst_attach_read(session, a, &n, err, sizeof(err));
    EXPECT(back && n == strlen(text) && memcmp(back, text, n) == 0,
           "text reads back exactly");
    free(back);
    EXPECT(cst_attach_data_url(session, a) == NULL,
           "a document has no data url");
    char desc[128];
    cst_attach_describe(a, desc, sizeof(desc));
    EXPECT(strstr(desc, "text") != NULL, "describe says text");
    cst_attach_free(a);
  }

  /* a one-page PDF with a text layer */
  static const char PDF[] =
      "%PDF-1.4\n"
      "1 0 obj\n<< /Type /Catalog /Pages 2 0 R >>\nendobj\n"
      "2 0 obj\n<< /Type /Pages /Kids [3 0 R] /Count 1 >>\nendobj\n"
      "3 0 obj\n<< /Type /Page /Parent 2 0 R /Resources << /Font << /F1 4 0 R "
      ">> >> /Contents 5 0 R >>\nendobj\n"
      "4 0 obj\n<< /Type /Font /Subtype /Type1 /BaseFont /Helvetica >>\n"
      "endobj\n"
      "5 0 obj\n<< >>\nstream\n"
      "BT /F1 12 Tf 72 720 Td (Attached paper abstract) Tj ET\n"
      "endstream\nendobj\n"
      "trailer\n<< /Root 1 0 R >>\n%%EOF\n";
  snprintf(src, sizeof(src), "%.900s/paper.pdf", root);
  f = fopen(src, "wb");
  EXPECT(f != NULL, "write the PDF");
  if (f) {
    fwrite(PDF, 1, strlen(PDF), f);
    fclose(f);
  }
  err[0] = 0;
  a = cst_attach_import_file(session, src, err, sizeof(err));
  EXPECT(a != NULL, "PDF imported");
  if (a) {
    EXPECT(strcmp(a->mime, "application/pdf") == 0, "the PDF keeps its mime");
    EXPECT(a->pages == 1, "page count comes from the extractor");
    EXPECT(strstr(a->rel, ".txt") != NULL, "the text layer is what is stored");
    EXPECT(cst_attach_is_text(a), "documents are text on the wire");
    char desc[128];
    cst_attach_describe(a, desc, sizeof(desc));
    EXPECT(strstr(desc, "pdf") != NULL && strstr(desc, "1 page") != NULL,
           "describe names the PDF and its pages");
    size_t n = 0;
    char *back = cst_attach_read(session, a, &n, err, sizeof(err));
    EXPECT(back && strstr(back, "Attached paper abstract") != NULL,
           "the extracted text reads back");
    free(back);
    cst_attach_free(a);
  }
  err[0] = 0;
  EXPECT(cst_attach_import_file(session, "/nonexistent/x.pdf", err,
                                sizeof(err)) == NULL,
         "a missing PDF is refused");

  /* neither image, PDF nor text: a binary blob */
  static const char binary[] = "\x01\x02\x03\x00\x04\x05";
  snprintf(src, sizeof(src), "%.900s/blob.bin", root);
  f = fopen(src, "wb");
  if (f) {
    fwrite(binary, 1, sizeof(binary), f);
    fclose(f);
  }
  err[0] = 0;
  EXPECT(cst_attach_import_file(session, src, err, sizeof(err)) == NULL,
         "a binary file is refused");
  EXPECT(strstr(err, "not an image") != NULL, "err says what was expected");
}

static void test_json_roundtrip(void) {
  cst_attachment_t list[3];
  memset(list, 0, sizeof(list));
  snprintf(list[0].id, sizeof(list[0].id), "img-1");
  snprintf(list[0].name, sizeof(list[0].name), "a.png");
  snprintf(list[0].mime, sizeof(list[0].mime), "image/png");
  snprintf(list[0].rel, sizeof(list[0].rel), "img-1.png");
  list[0].bytes = 12345;
  list[0].width = 640;
  list[0].height = 480;
  snprintf(list[0].origin, sizeof(list[0].origin), "user");

  snprintf(list[1].id, sizeof(list[1].id), "img-2");
  snprintf(list[1].name, sizeof(list[1].name), "b.jpg");
  snprintf(list[1].mime, sizeof(list[1].mime), "image/jpeg");
  snprintf(list[1].rel, sizeof(list[1].rel), "img-2.jpg");
  list[1].bytes = 4096;
  snprintf(list[1].detail, sizeof(list[1].detail), "high");
  snprintf(list[1].origin, sizeof(list[1].origin), "view_image");
  snprintf(list[1].mime, sizeof(list[1].mime), "application/pdf");
  list[1].pages = 12;

  snprintf(list[2].id, sizeof(list[2].id), "img-3");
  snprintf(list[2].name, sizeof(list[2].name), "c.webp");
  snprintf(list[2].mime, sizeof(list[2].mime), "image/webp");
  snprintf(list[2].rel, sizeof(list[2].rel), "img-3.webp");
  list[2].bytes = 7;

  char *json = cst_attachments_to_json(list, 3);
  EXPECT(json != NULL, "to_json");
  int n = 0;
  cJSON *parsed = cJSON_Parse(json);
  cst_attachment_t *back = cst_attachments_from_json(parsed, &n);
  cJSON_Delete(parsed);
  EXPECT(back != NULL && n == 3, "from_json count");
  if (back && n == 3) {
    EXPECT(strcmp(back[0].id, "img-1") == 0 && back[0].bytes == 12345 &&
               back[0].width == 640 && back[0].height == 480,
           "first entry survives");
    EXPECT(strcmp(back[1].detail, "high") == 0 &&
               strcmp(back[1].origin, "view_image") == 0,
           "detail and origin survive");
    EXPECT(strcmp(back[1].mime, "application/pdf") == 0 && back[1].pages == 12,
           "a document keeps its mime and page count");
    EXPECT(back[2].pages == 0, "pages default to 0");
    EXPECT(strcmp(back[2].mime, "image/webp") == 0 && back[2].width == 0,
           "entry without dimensions");
    EXPECT(strcmp(back[0].detail, "auto") == 0, "missing detail defaults");
    cst_attachments_free(back, n);
  }
  free(json);

  /* entries without rel/id are dropped; a non-array is NULL */
  cJSON *arr = cJSON_Parse("[{\"id\":\"x\"},{\"id\":\"y\",\"rel\":\"y.png\"}]");
  back = cst_attachments_from_json(arr, &n);
  EXPECT(back != NULL && n == 1 && strcmp(back[0].id, "y") == 0,
         "incomplete entries skipped");
  cst_attachments_free(back, n);
  cJSON_Delete(arr);
  cJSON *obj = cJSON_Parse("{}");
  n = 7;
  EXPECT(cst_attachments_from_json(obj, &n) == NULL && n == 0,
         "object is not an attachment array");
  cJSON_Delete(obj);
  EXPECT(cst_attachments_to_json(NULL, 0) == NULL, "empty list is NULL");
}

static void test_lists(void) {
  cst_attachment_t src;
  memset(&src, 0, sizeof(src));
  snprintf(src.id, sizeof(src.id), "img-x");
  snprintf(src.mime, sizeof(src.mime), "image/png");

  cst_attachment_t *list = NULL;
  int n = 0, cap = 0;
  for (int i = 0; i < 10; i++)
    EXPECT(cst_attachments_push(&list, &n, &cap, &src) == 0, "push");
  EXPECT(n == 10 && cap >= 10, "list grew");
  EXPECT(strcmp(list[9].id, "img-x") == 0, "last entry copied");

  cst_attachment_t *dup = cst_attachments_dup(list, n);
  EXPECT(dup && strcmp(dup[3].mime, "image/png") == 0, "dup copies fields");
  dup[3].id[0] = 'Z';
  EXPECT(list[3].id[0] == 'i', "dup is a deep copy");
  cst_attachments_free(dup, n);
  EXPECT(cst_attachments_dup(NULL, 0) == NULL, "dup of nothing is NULL");
  cst_attachments_free(list, n);
}

static void test_agent_pending(const char *root) {
  cst_agent_config_t cfg;
  memset(&cfg, 0, sizeof(cfg));
  snprintf(cfg.workspace_root, sizeof(cfg.workspace_root), "%s", root);
  snprintf(cfg.session_path, sizeof(cfg.session_path), "%s/sessions/c.jsonl",
           root);
  cst_agent_t *a = cst_agent_create(&cfg);
  EXPECT(a != NULL, "agent created");
  if (!a)
    return;

  char err[256], line[128];
  EXPECT(cst_agent_pending_count(a) == 0, "no pending at start");
  EXPECT(cst_agent_pending_describe(a, 0, line, sizeof(line)) == -1,
         "describe out of range");

  unsigned char b[32];
  size_t n = png_hdr(b, 4, 2);
  char src[1024];
  snprintf(src, sizeof(src), "%.900s/pic.png", root);
  FILE *f = fopen(src, "wb");
  EXPECT(f != NULL, "write the source png");
  if (f) {
    fwrite(b, 1, n, f);
    fclose(f);
  }
  EXPECT(cst_agent_attach_file(a, src, err, sizeof(err)) == 0,
         "attach through the agent");
  EXPECT(cst_agent_pending_count(a) == 1, "one pending");
  EXPECT(cst_agent_pending_describe(a, 0, line, sizeof(line)) == 0 &&
             strstr(line, "4x2") != NULL,
         "pending describe shows the size");

  EXPECT(cst_agent_attach_file(a, "/nonexistent/x.png", err, sizeof(err)) == -1,
         "missing file refused");
  EXPECT(cst_agent_pending_count(a) == 1, "a failure keeps the queue");

  for (int i = 1; i < CST_ATTACH_MAX_COUNT; i++)
    EXPECT(cst_agent_attach_file(a, src, err, sizeof(err)) == 0, "attach more");
  EXPECT(cst_agent_pending_count(a) == CST_ATTACH_MAX_COUNT, "queue full");
  EXPECT(cst_agent_attach_file(a, src, err, sizeof(err)) == -1 &&
             strstr(err, "at most") != NULL,
         "one over the limit is refused");

  cst_agent_pending_clear(a);
  EXPECT(cst_agent_pending_count(a) == 0, "cleared");
  cst_agent_destroy(a);
}

static void test_paste_paths(void) {
  static char p[CST_PASTE_MAX_PATHS][CST_PASTE_PATH_MAX];
  const char *s = "/tmp/a.png";
  EXPECT(cst_paste_paths(s, strlen(s), p, 8) == 1 &&
             strcmp(p[0], "/tmp/a.png") == 0,
         "single path");
  s = "  '/home/u/my shot.png' \"/x/y z.jpg\"\n/plain.gif\r\n";
  EXPECT(cst_paste_paths(s, strlen(s), p, 8) == 3, "quoted paths count");
  EXPECT(strcmp(p[0], "/home/u/my shot.png") == 0, "single quotes");
  EXPECT(strcmp(p[1], "/x/y z.jpg") == 0, "double quotes");
  EXPECT(strcmp(p[2], "/plain.gif") == 0, "newline separated");
  s = "file:///home/u/a%20b.png file://localhost/c.png";
  EXPECT(cst_paste_paths(s, strlen(s), p, 8) == 2, "file uris");
  EXPECT(strcmp(p[0], "/home/u/a b.png") == 0, "percent decoded");
  EXPECT(strcmp(p[1], "/c.png") == 0, "localhost host");
  s = "file://evil.example/c.png";
  EXPECT(cst_paste_paths(s, strlen(s), p, 8) == -1, "remote host refused");
#ifndef _WIN32
  s = "/home/u/my\\ shot.png";
  EXPECT(cst_paste_paths(s, strlen(s), p, 8) == 1 &&
             strcmp(p[0], "/home/u/my shot.png") == 0,
         "backslash escape");
#endif
  s = "'/unterminated.png";
  EXPECT(cst_paste_paths(s, strlen(s), p, 8) == -1, "unbalanced quote");
  s = "   \n ";
  EXPECT(cst_paste_paths(s, strlen(s), p, 8) == -1, "blank");
  s = "a b c";
  EXPECT(cst_paste_paths(s, strlen(s), p, 2) == -1, "too many");
}

static void test_dib(void) {
  /* 3x2, 24-bit, bottom-up: stride 12 (9 bytes + pad). */
  unsigned char dib[40 + 24];
  memset(dib, 0, sizeof(dib));
  put_le32(dib, 40);
  put_le32(dib + 4, 3);
  put_le32(dib + 8, 2);
  put_le16(dib + 12, 1);
  put_le16(dib + 14, 24);
  dib[40] = 0xff; /* bottom-left pixel blue (BGR) */
  size_t n = 0;
  char *img = cst_dib_to_image(dib, sizeof(dib), &n);
  char mime[32];
  int w = 0, h = 0;
  EXPECT(img && cst_attach_sniff(img, n, mime, sizeof(mime)) == 0 &&
             strcmp(mime, "image/png") == 0,
         "24-bit DIB becomes a PNG");
  EXPECT(img && cst_attach_dimensions(img, n, &w, &h) == 0 && w == 3 && h == 2,
         "PNG keeps the size");
  free(img);

  put_le16(dib + 14, 8); /* palette needs 256 entries: past the end */
  EXPECT(cst_dib_to_image(dib, sizeof(dib), &n) == NULL, "short DIB refused");
  put_le32(dib, 4);
  EXPECT(cst_dib_to_image(dib, sizeof(dib), &n) == NULL, "bad header size");
}

int main(void) {
  char root[1024];
  if (test_tmpdir(root, sizeof(root), "cst-attach") != 0) {
    fprintf(stderr, "cannot create a scratch dir\n");
    return 1;
  }
  test_sniff();
  test_dimensions();
  test_base64();
  test_rel_ok(root);
  test_paste_paths();
  test_dib();
  test_store(root);
  test_import_file(root);
  test_documents(root);
  test_json_roundtrip();
  test_lists();
  test_agent_pending(root);
  test_rmrf(root);
  if (nfail) {
    fprintf(stderr, "test_attach: %d failed\n", nfail);
    return 1;
  }
  printf("test_attach: OK\n");
  return 0;
}