MeowOS-For-R3P2/patch_v2/meow_audiod/bt_dev.c

/* bt_dev.c — 蓝牙 A2DP 端点选择 + PCM 名构造 + 回落退避（纯逻辑实现，见 bt_dev.h 契约）。
 *
 * 纯 libc（string / stdlib），无任何 meow_* 调用、无 popen、无文件 I/O —— meow_audiod 负责
 * 执行 `bluealsa-cli list-pcms`、调用 libasound 及维护运行时状态。
 */
#include "bt_dev.h"

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

/* 是否 a2dpsrc / a2dp_source 端点行（bluealsa 4.1.1 list-pcms 的端点头） */
static int is_src_line(const char *p)
{
    return strstr(p, "a2dpsrc") != NULL || strstr(p, "a2dp_source") != NULL;
}

/* 从 D-Bus 对象路径取 MAC。bluealsa 4.1.1 的 PCM 路径是
 *   /org/bluealsa/hci0/dev_33_DE_2E_21_AD_30/a2dpsrc/source
 * （dev_%.2X_%.2X_%.2X_%.2X_%.2X_%.2X，见 src/ba-transport.c / src/shared/dbus-client.c）。
 * 返回 0=解析出 17 字符 MAC（大写、冒号分隔）。 */
static int parse_dev_seg(const char *line, char *mac, size_t macsz)
{
    if (!line || !mac || macsz < 18) return -1;
    const char *d = strstr(line, "dev_");
    if (!d) return -1;
    const char *p = d + 4;
    char out[18];
    size_t o = 0;
    for (int i = 0; i < 6; i++) {
        unsigned v = 0;
        int digits = 0;
        for (; digits < 2; digits++) {
            char c = *p;
            int h = -1;
            if (c >= '0' && c <= '9') h = c - '0';
            else if (c >= 'A' && c <= 'F') h = c - 'A' + 10;
            else if (c >= 'a' && c <= 'f') h = c - 'a' + 10;
            if (h < 0) break;
            v = v * 16u + (unsigned)h;
            p++;
        }
        if (digits == 0) return -1;
        o += (size_t)snprintf(out + o, sizeof out - o, (i == 0) ? "%02X" : ":%02X", v);
        if (i < 5) {
            if (*p != '_') return -1;
            p++;
        }
    }
    if (o != 17) return -1;
    memcpy(mac, out, 18);
    return 0;
}

/* 兜底：端点 token 的最后一段直接是 MAC（老式/简化输出 `a2dpsrc/AA:BB:...`）。 */
static int parse_tail_mac(const char *hit, char *mac, size_t macsz)
{
    const char *te = hit;
    while (*te && *te != ' ' && *te != '\t' && *te != '\n') te++;
    const char *slash = NULL;
    for (const char *q = hit; q < te; q++) if (*q == '/') slash = q;
    if (!slash || (slash + 1) >= te) return -1;
    const char *start = slash + 1;
    size_t len = (size_t)(te - start);
    if (len != 17 || len >= macsz) return -1;
    int colons = 0;
    for (size_t i = 0; i < len; i++) if (start[i] == ':') colons++;
    if (colons != 5) return -1;
    memcpy(mac, start, len);
    mac[len] = 0;
    return 0;
}

/* 解析 bluealsa-cli list-pcms 输出，取第一个 a2dpsrc/a2dp_source 端点的设备 MAC。
 * 真实输出是 D-Bus 对象路径（每行一个）：
 *   /org/bluealsa/hci0/dev_33_DE_2E_21_AD_30/a2dpsrc/source
 * MAC 取自 `dev_XX_XX_XX_XX_XX_XX` 段（下划线 → 冒号），另兼容简化形式 `a2dpsrc/AA:BB:...`。
 * 逐个**有界行**匹配（strstr 必须在行内，避免跨换行误把后一行当本行端点——如行 1
 * "hfphf/sink" 与行 3 "a2dpsrc/source" 的经典误判）。 */
int bt_dev_detect_mac(const char *listpcms, char *mac, size_t macsz)
{
    if (!listpcms || !mac || macsz < 2) return -1;
    mac[0] = 0;
    const char *ln = listpcms;
    while (ln && *ln) {
        const char *nl = strchr(ln, '\n');
        const char *le = nl ? nl : (ln + strlen(ln));
        size_t linelen = (size_t)(le - ln);
        char line[256];
        if (linelen >= sizeof line) linelen = sizeof line - 1;
        memcpy(line, ln, linelen); line[linelen] = 0;
        const char *p = line;
        while (*p == ' ' || *p == '\t') p++;
        if (is_src_line(p)) {
            if (parse_dev_seg(p, mac, macsz) == 0) return 0;
            const char *hit = strstr(p, "a2dpsrc");
            if (!hit) hit = strstr(p, "a2dp_source");
            if (hit && parse_tail_mac(hit, mac, macsz) == 0) return 0;
        }
        if (!nl) break;
        ln = nl + 1;
    }
    mac[0] = 0;
    return -1;
}

int bt_dev_count_src(const char *listpcms)
{
    if (!listpcms) return 0;
    int n = 0;
    const char *ln = listpcms;
    while (ln && *ln) {
        const char *nl = strchr(ln, '\n');
        const char *p = ln;
        while (*p == ' ' || *p == '\t') p++;
        if (is_src_line(p)) n++;
        if (!nl) break;
        ln = nl + 1;
    }
    return n;
}

/* bluealsa 4.1.1 src/shared/a2dp-codecs.c 的 canonical 名与别名（strcasecmp 匹配）。
 * 只列本机可达的音频 codec；auto/unchanged/未知 → unchanged（不干预协商）。 */
static const struct {
    const char *canonical;
    const char *aliases[4];
} codecs[] = {
    { "SBC",        { "SBC", NULL } },
    { "MP3",        { "MP3", "MPEG12", "MPEG", NULL } },
    { "AAC",        { "AAC", "MPEG24", NULL } },
    { "ATRAC",      { "ATRAC", NULL } },
    { "aptX",       { "aptX", "apt-X", NULL } },
    { "aptX-AD",    { "aptX-AD", "apt-X-AD", NULL } },
    { "aptX-HD",    { "aptX-HD", "apt-X-HD", NULL } },
    { "aptX-LL",    { "aptX-LL", "apt-X-LL", NULL } },
    { "aptX-TWS",   { "aptX-TWS", "apt-X-TWS", NULL } },
    { "FastStream", { "FastStream", "FS", NULL } },
    { "LC3plus",    { "LC3plus", NULL } },
    { "LDAC",       { "LDAC", NULL } },
    { "LHDC",       { "LHDC", NULL } },
};

const char *bt_dev_codec_token(const char *setting, char *out, size_t outsz)
{
    const char *auto_tok = "unchanged";
    if (!out || outsz < 2) return auto_tok;
    if (!setting || !setting[0]) { snprintf(out, outsz, "%s", auto_tok); return out; }
    if (!strcasecmp(setting, "auto") || !strcasecmp(setting, "unchanged")) {
        snprintf(out, outsz, "%s", auto_tok);
        return out;
    }
    for (size_t i = 0; i < sizeof codecs / sizeof codecs[0]; i++)
        for (size_t n = 0; n < 4 && codecs[i].aliases[n]; n++)
            if (!strcasecmp(codecs[i].aliases[n], setting)) {
                snprintf(out, outsz, "%s", codecs[i].canonical);
                return out;
            }
    snprintf(out, outsz, "%s", auto_tok);   /* 未知值：不干预协商（不把垃圾塞进 PCM 名） */
    return out;
}

/* MAC 合法性：6 组两位十六进制，'/' 或 ':' 分隔都不接受（只认冒号，bluealsa 约定）。 */
static int mac_valid(const char *mac)
{
    if (!mac || strlen(mac) != 17) return 0;
    for (int i = 0; i < 17; i++) {
        if ((i % 3) == 2) { if (mac[i] != ':') return 0; }
        else {
            char c = mac[i];
            int hex = (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F');
            if (!hex) return 0;
        }
    }
    return 1;
}

int bt_dev_pcm_name(const char *mac, const char *codec_token, char *out, size_t outsz)
{
    if (!out || outsz < 32 || !mac_valid(mac)) return -1;
    const char *tok = (codec_token && codec_token[0]) ? codec_token : "unchanged";
    int n = snprintf(out, outsz, "bluealsa:DEV=%s,PROFILE=a2dp,CODEC=%s", mac, tok);
    if (n < 0 || (size_t)n >= outsz) { out[0] = 0; return -1; }
    return 0;
}

unsigned bt_dev_backoff_ms(unsigned fails)
{
    if (fails == 0) return 0;
    unsigned shift = fails - 1;
    if (shift > 5) shift = 5;
    unsigned long d = 2000UL << shift;      /* 2s,4s,8s,16s,32s,64s */
    if (d > 60000UL) d = 60000UL;
    return (unsigned)d;
}

int bt_dev_should_try(unsigned fails, long long since_ms)
{
    if (fails == 0) return 1;
    if (since_ms < 0) return 1;
    return since_ms >= (long long)bt_dev_backoff_ms(fails) ? 1 : 0;
}