libhv/http/server/FileCache.h

#ifndef HW_FILE_CACHE_H_
#define HW_FILE_CACHE_H_

#include <map>
#include <string>

#include "hbuf.h"
#include "hfile.h"
#include "hstring.h"

#define HTTP_HEADER_MAX_LENGTH      1024 // 1k

typedef struct file_cache_s {
    //std::string filepath;
    struct stat st;
    time_t      open_time;
    time_t      stat_time;
    uint32_t    stat_cnt;
    HBuf        buf; // http_header + file_content
    hbuf_t      filebuf;
    hbuf_t      httpbuf;
    char        last_modified[64];
    char        etag[64];
    const char* content_type;

    file_cache_s() {
        stat_cnt = 0;
        content_type = NULL;
    }

    void resize_buf(int filesize) {
        buf.resize(HTTP_HEADER_MAX_LENGTH + filesize);
        filebuf.base = buf.base + HTTP_HEADER_MAX_LENGTH;
        filebuf.len = filesize;
    }

    void prepend_header(const char* header, int len) {
        if (len > HTTP_HEADER_MAX_LENGTH) return;
        httpbuf.base = filebuf.base - len;
        httpbuf.len = len + filebuf.len;
        memcpy(httpbuf.base, header, len);
    }
} file_cache_t;

// filepath => file_cache_t
typedef std::map<std::string, file_cache_t*> FileCacheMap;

#define DEFAULT_FILE_STAT_INTERVAL  10 // s
#define DEFAULT_FILE_CACHED_TIME    60 // s
class FileCache {
public:
    int file_stat_interval;
    int file_cached_time;
    FileCacheMap cached_files;

    FileCache() {
        file_stat_interval  = DEFAULT_FILE_STAT_INTERVAL;
        file_cached_time    = DEFAULT_FILE_CACHED_TIME;
    }

    ~FileCache() {
        for (auto& pair : cached_files) {
            delete pair.second;
        }
        cached_files.clear();
    }

    file_cache_t* Open(const char* filepath, void* ctx = NULL);
    int Close(const char* filepath);
protected:
    file_cache_t* Get(const char* filepath);
};

#endif // HW_FILE_CACHE_H_