Define bounded typed attachment metadata for PM and GUI

src/media_async/attachment.c

@@ -0,0 +1,87 @@
+/* Ограниченный бинарный формат: kind:1, name_len:2, duration_ms:4, width:2,
+ * height:2, UTF-8 name, waveform:100 для voice. Числа big-endian. */
+#include <string.h>
+#include "../../lib/debug_config.h"
+#include "attachment.h"
+
+/* Имя должно быть корректным UTF-8 basename без управляющих символов. */
+static int valid_name(const char* name, size_t n) {
+    if (!n || n > 255 || (n == 1 && name[0] == '.') || (n == 2 && !memcmp(name, "..", 2))) return 0;
+    for (size_t i = 0; i < n;) {
+        unsigned c = (unsigned char)name[i++];
+        if (c < 0x20 || c == 0x7f || c == '/' || c == '\\') return 0;
+        if (c < 0x80) continue;
+        unsigned count, scalar, minimum;
+        if (c >= 0xc2 && c <= 0xdf) { count = 1; scalar = c & 31; minimum = 0x80; }
+        else if (c >= 0xe0 && c <= 0xef) { count = 2; scalar = c & 15; minimum = 0x800; }
+        else if (c >= 0xf0 && c <= 0xf4) { count = 3; scalar = c & 7; minimum = 0x10000; }
+        else return 0;
+        if (count > n - i) return 0;
+        while (count--) {
+            c = (unsigned char)name[i++];
+            if ((c & 0xc0) != 0x80) return 0;
+            scalar = (scalar << 6) | (c & 63);
+        }
+        if (scalar < minimum || scalar > 0x10ffff || (scalar >= 0xd800 && scalar <= 0xdfff)) return 0;
+    }
+    return 1;
+}
+
+/* Один набор правил для отправки, приёма и снимка истории. */
+int attachment_validate(const struct attachment_info* info) {
+    if (!info || !valid_name(info->name, strnlen(info->name, sizeof(info->name)))) goto invalid;
+    size_t wave = strnlen(info->waveform, sizeof(info->waveform));
+    if (info->kind == ATTACHMENT_VOICE) {
+        if (!info->duration_ms || info->duration_ms > 86400000 || info->width || info->height || wave != 100) goto invalid;
+        if (strspn(info->waveform, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/") != wave) goto invalid;
+    } else {
+        if (wave) goto invalid;
+        if (info->kind == ATTACHMENT_FILE) {
+            if (info->duration_ms || info->width || info->height) goto invalid;
+        } else if (info->kind == ATTACHMENT_VIDEO || info->kind == ATTACHMENT_IMAGE) {
+            if (!info->width || !info->height || info->width > 16384 || info->height > 16384) goto invalid;
+            if (info->kind == ATTACHMENT_VIDEO ? (!info->duration_ms || info->duration_ms > 86400000) : info->duration_ms) goto invalid;
+        } else goto invalid;
+    }
+    return 0;
+invalid:
+    DEBUG_WARN(DEBUG_CATEGORY_MEDIA, "attachment: invalid metadata kind=%d", info ? (int)info->kind : 0);
+    return -1;
+}
+
+int attachment_encode(const struct attachment_info* info, uint8_t* out, size_t capacity) {
+    if (attachment_validate(info)) return -1;
+    size_t n = strlen(info->name), length = 11 + n + (info->kind == ATTACHMENT_VOICE ? 100 : 0);
+    if (!out || capacity < length) { DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "attachment: encode buffer too small"); return -1; }
+    out[0] = (uint8_t)info->kind; out[1] = (uint8_t)(n >> 8); out[2] = (uint8_t)n;
+    for (unsigned i = 0; i < 4; i++) out[3 + i] = (uint8_t)(info->duration_ms >> (24 - 8 * i));
+    out[7] = (uint8_t)(info->width >> 8); out[8] = (uint8_t)info->width;
+    out[9] = (uint8_t)(info->height >> 8); out[10] = (uint8_t)info->height;
+    memcpy(out + 11, info->name, n);
+    if (info->kind == ATTACHMENT_VOICE) memcpy(out + 11 + n, info->waveform, 100);
+    return (int)length;
+}
+
+int attachment_decode(const uint8_t* data, size_t length, struct attachment_info* info) {
+    if (!data || !info || length < 11) goto invalid;
+    size_t n = ((size_t)data[1] << 8) | data[2];
+    if (!n || n > 255 || length != 11 + n + (data[0] == ATTACHMENT_VOICE ? 100 : 0) || memchr(data + 11, 0, n)) goto invalid;
+    memset(info, 0, sizeof(*info)); info->kind = (enum attachment_kind)data[0];
+    for (unsigned i = 0; i < 4; i++) info->duration_ms = (info->duration_ms << 8) | data[3 + i];
+    info->width = (uint16_t)((data[7] << 8) | data[8]); info->height = (uint16_t)((data[9] << 8) | data[10]);
+    memcpy(info->name, data + 11, n);
+    if (info->kind == ATTACHMENT_VOICE) memcpy(info->waveform, data + 11 + n, 100);
+    return attachment_validate(info);
+invalid:
+    DEBUG_WARN(DEBUG_CATEGORY_MEDIA, "attachment: malformed wire metadata bytes=%zu", length);
+    return -1;
+}
+
+const char* attachment_content_type(enum attachment_kind kind) {
+    switch (kind) {
+    case ATTACHMENT_VOICE: return "audio/opus";
+    case ATTACHMENT_VIDEO: return "video/mp4";
+    case ATTACHMENT_IMAGE: return "image/jpeg";
+    default: return "application/octet-stream";
+    }
+}

src/media_async/attachment.h

@@ -0,0 +1,30 @@
+/* Общие метаданные готового вложения. Подготовка не знает адресата и транспорта.
+ * PM шифрует компактный wire-формат; GUI получает разобранные поля.
+ * encode/decode возвращают длину/0 или -1; неизвестные типы и лишние байты запрещены. */
+#ifndef ATTACHMENT_H
+#define ATTACHMENT_H
+#include <stdint.h>
+#include <stddef.h>
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+enum attachment_kind { ATTACHMENT_FILE = 1, ATTACHMENT_VOICE, ATTACHMENT_VIDEO, ATTACHMENT_IMAGE };
+#define ATTACHMENT_WAVE_SIZE 100
+#define ATTACHMENT_WIRE_MAX (11 + 255 + ATTACHMENT_WAVE_SIZE)
+struct attachment_info {
+    enum attachment_kind kind;
+    char name[256];
+    uint32_t duration_ms;
+    uint16_t width, height;
+    char waveform[ATTACHMENT_WAVE_SIZE + 1]; /* 100 уровней из A-Za-z0-9+/; только voice. */
+};
+int attachment_validate(const struct attachment_info* info);
+int attachment_encode(const struct attachment_info* info, uint8_t* out, size_t capacity);
+int attachment_decode(const uint8_t* data, size_t length, struct attachment_info* info);
+const char* attachment_content_type(enum attachment_kind kind);
+
+#ifdef __cplusplus
+}
+#endif
+#endif