feat: Enhance filecache

http/server/FileCache.cpp

@@ -14,9 +14,12 @@
 
 #define ETAG_FMT    "\"%zx-%zx\""
 
-FileCache::FileCache(size_t capacity) : hv::LRUCache<std::string, file_cache_ptr>(capacity) {
-    stat_interval = 10; // s
-    expired_time  = 60; // s
+FileCache::FileCache(size_t capacity)
+    : hv::LRUCache<std::string, file_cache_ptr>(capacity) {
+    stat_interval    = 10;  // s
+    expired_time     = 60;  // s
+    max_header_length = FILE_CACHE_DEFAULT_HEADER_LENGTH;
+    max_file_size    = FILE_CACHE_DEFAULT_MAX_FILE_SIZE;
 }
 
 file_cache_ptr FileCache::Open(const char* filepath, OpenParam* param) {
@@ -26,6 +29,7 @@ file_cache_ptr FileCache::Open(const char* filepath, OpenParam* param) {
 #endif
     bool modified = false;
     if (fc) {
+        std::lock_guard<std::mutex> lock(fc->mutex);
         time_t now = time(NULL);
         if (now - fc->stat_time > stat_interval) {
             fc->stat_time = now;
@@ -52,85 +56,112 @@ file_cache_ptr FileCache::Open(const char* filepath, OpenParam* param) {
         flags |= O_BINARY;
 #endif
         int fd = -1;
+        bool is_dir = false;
 #ifdef OS_WIN
-        if(wfilepath.empty()) wfilepath = hv::utf8_to_wchar(filepath);
-        if(_wstat(wfilepath.c_str(), (struct _stat*)&st) != 0) {
+        if (wfilepath.empty()) wfilepath = hv::utf8_to_wchar(filepath);
+        if (_wstat(wfilepath.c_str(), (struct _stat*)&st) != 0) {
             param->error = ERR_OPEN_FILE;
             return NULL;
         }
-        if(S_ISREG(st.st_mode)) {
+        if (S_ISREG(st.st_mode)) {
             fd = _wopen(wfilepath.c_str(), flags);
-        }else if (S_ISDIR(st.st_mode)) {
-            // NOTE: open(dir) return -1 on windows
-            fd = 0;
+        } else if (S_ISDIR(st.st_mode)) {
+            is_dir = true;
         }
 #else
-        if(stat(filepath, &st) != 0) {
+        if (::stat(filepath, &st) != 0) {
             param->error = ERR_OPEN_FILE;
             return NULL;
         }
         fd = open(filepath, flags);
 #endif
-        if (fd < 0) {
+        if (fd < 0 && !is_dir) {
             param->error = ERR_OPEN_FILE;
             return NULL;
         }
-        defer(if (fd > 0) { close(fd); })
+        defer(if (fd >= 0) { close(fd); })
         if (fc == NULL) {
             if (S_ISREG(st.st_mode) ||
                 (S_ISDIR(st.st_mode) &&
-                 filepath[strlen(filepath)-1] == '/')) {
+                 filepath[strlen(filepath) - 1] == '/')) {
                 fc = std::make_shared<file_cache_t>();
                 fc->filepath = filepath;
                 fc->st = st;
+                fc->header_reserve = max_header_length;
                 time(&fc->open_time);
                 fc->stat_time = fc->open_time;
                 fc->stat_cnt = 1;
-                put(filepath, fc);
-            }
-            else {
+                // NOTE: do NOT put() into cache yet — defer until fully initialized
+            } else {
                 param->error = ERR_MISMATCH;
                 return NULL;
             }
         }
-        if (S_ISREG(fc->st.st_mode)) {
-            param->filesize = fc->st.st_size;
-            // FILE
-            if (param->need_read) {
-                if (fc->st.st_size > param->max_read) {
-                    param->error = ERR_OVER_LIMIT;
-                    return NULL;
+        // Hold fc->mutex for initialization, but release before put()
+        // to avoid lock-order inversion with RemoveExpiredFileCache().
+        // Lock order: LRUCache mutex → fc->mutex (never reverse).
+        {
+            std::lock_guard<std::mutex> lock(fc->mutex);
+            if (S_ISREG(st.st_mode)) {
+                param->filesize = st.st_size;
+                // FILE
+                if (param->need_read) {
+                    if (st.st_size > param->max_read) {
+                        param->error = ERR_OVER_LIMIT;
+                        // Leave existing cache entry's state untouched
+                        return NULL;
+                    }
                 }
-                fc->resize_buf(fc->st.st_size);
-                int nread = read(fd, fc->filebuf.base, fc->filebuf.len);
-                if (nread != fc->filebuf.len) {
-                    hloge("Failed to read file: %s", filepath);
-                    param->error = ERR_READ_FILE;
-                    return NULL;
+                // Validation passed — commit new stat into cached entry
+                fc->st = st;
+                if (param->need_read) {
+                    fc->resize_buf(fc->st.st_size, max_header_length);
+                    // Loop to handle partial reads (EINTR, etc.)
+                    char* dst = fc->filebuf.base;
+                    size_t remaining = fc->filebuf.len;
+                    while (remaining > 0) {
+                        int nread = read(fd, dst, remaining);
+                        if (nread < 0) {
+                            if (errno == EINTR) continue;
+                            hloge("Failed to read file: %s", filepath);
+                            param->error = ERR_READ_FILE;
+                            return NULL;
+                        }
+                        if (nread == 0) {
+                            hloge("Unexpected EOF reading file: %s", filepath);
+                            param->error = ERR_READ_FILE;
+                            return NULL;
+                        }
+                        dst += nread;
+                        remaining -= nread;
+                    }
                 }
-            }
-            const char* suffix = strrchr(filepath, '.');
-            if (suffix) {
-                http_content_type content_type = http_content_type_enum_by_suffix(suffix+1);
-                if (content_type == TEXT_HTML) {
-                    fc->content_type = "text/html; charset=utf-8";
-                } else if (content_type == TEXT_PLAIN) {
-                    fc->content_type = "text/plain; charset=utf-8";
-                } else {
-                    fc->content_type = http_content_type_str_by_suffix(suffix+1);
+                const char* suffix = strrchr(filepath, '.');
+                if (suffix) {
+                    http_content_type content_type = http_content_type_enum_by_suffix(suffix + 1);
+                    if (content_type == TEXT_HTML) {
+                        fc->content_type = "text/html; charset=utf-8";
+                    } else if (content_type == TEXT_PLAIN) {
+                        fc->content_type = "text/plain; charset=utf-8";
+                    } else {
+                        fc->content_type = http_content_type_str_by_suffix(suffix + 1);
+                    }
                 }
+            } else if (S_ISDIR(st.st_mode)) {
+                // DIR
+                fc->st = st;
+                std::string page;
+                make_index_of_page(filepath, page, param->path);
+                fc->resize_buf(page.size(), max_header_length);
+                memcpy(fc->filebuf.base, page.c_str(), page.size());
+                fc->content_type = "text/html; charset=utf-8";
             }
-        }
-        else if (S_ISDIR(fc->st.st_mode)) {
-            // DIR
-            std::string page;
-            make_index_of_page(filepath, page, param->path);
-            fc->resize_buf(page.size());
-            memcpy(fc->filebuf.base, page.c_str(), page.size());
-            fc->content_type = "text/html; charset=utf-8";
-        }
-        gmtime_fmt(fc->st.st_mtime, fc->last_modified);
-        snprintf(fc->etag, sizeof(fc->etag), ETAG_FMT, (size_t)fc->st.st_mtime, (size_t)fc->st.st_size);
+            gmtime_fmt(fc->st.st_mtime, fc->last_modified);
+            snprintf(fc->etag, sizeof(fc->etag), ETAG_FMT,
+                     (size_t)fc->st.st_mtime, (size_t)fc->st.st_size);
+        } // release fc->mutex before put() to maintain lock ordering
+        // Cache the fully initialized entry (acquires LRUCache mutex only)
+        put(filepath, fc);
     }
     return fc;
 }
@@ -154,6 +185,12 @@ file_cache_ptr FileCache::Get(const char* filepath) {
 void FileCache::RemoveExpiredFileCache() {
     time_t now = time(NULL);
     remove_if([this, now](const std::string& filepath, const file_cache_ptr& fc) {
+        // Use try_to_lock to avoid lock-order inversion with Open().
+        // If the entry is busy, skip it — it will be checked next cycle.
+        std::unique_lock<std::mutex> lock(fc->mutex, std::try_to_lock);
+        if (!lock.owns_lock()) {
+            return false;
+        }
         return (now - fc->stat_time > expired_time);
     });
 }

http/server/FileCache.h

@@ -1,90 +1,158 @@
 #ifndef HV_FILE_CACHE_H_
 #define HV_FILE_CACHE_H_
 
+/*
+ * FileCache — Enhanced File Cache for libhv HTTP server
+ *
+ * Features:
+ *   1. Configurable max_header_length (default 4096, tunable per-instance)
+ *   2. prepend_header() returns bool to report success/failure
+ *   3. Exposes header/buffer metrics via accessors
+ *   4. Fixes stat() name collision in is_modified()
+ *   5. max_cache_num / max_file_size configurable at runtime
+ *   6. Reserved header space can be tuned per-instance
+ *   7. Source-level API compatible; struct layout differs from original (no ABI/layout compatibility)
+ */
+
 #include <memory>
-#include <map>
 #include <string>
 #include <mutex>
 
+#include "hexport.h"
 #include "hbuf.h"
 #include "hstring.h"
 #include "LRUCache.h"
 
-#define HTTP_HEADER_MAX_LENGTH      1024        // 1K
-#define FILE_CACHE_MAX_NUM          100
-#define FILE_CACHE_MAX_SIZE         (1 << 22)   // 4M
+// Default values — may be overridden at runtime via FileCache setters
+#define FILE_CACHE_DEFAULT_HEADER_LENGTH  4096        // 4K
+#define FILE_CACHE_DEFAULT_MAX_NUM        100
+#define FILE_CACHE_DEFAULT_MAX_FILE_SIZE  (1 << 22)   // 4M
 
 typedef struct file_cache_s {
+    mutable std::mutex  mutex;      // protects all mutable state below
     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;
+    HBuf        buf;        // header_reserve + file_content
+    hbuf_t      filebuf;    // points into buf: file content region
+    hbuf_t      httpbuf;    // points into buf: header + file content after prepend
     char        last_modified[64];
     char        etag[64];
     std::string content_type;
 
+    // --- new: expose header metrics ---
+    int         header_reserve;     // reserved bytes before file content
+    int         header_used;        // actual bytes used by prepend_header
+
     file_cache_s() {
         stat_cnt = 0;
+        header_reserve = FILE_CACHE_DEFAULT_HEADER_LENGTH;
+        header_used = 0;
+        memset(last_modified, 0, sizeof(last_modified));
+        memset(etag, 0, sizeof(etag));
     }
 
+    // NOTE: caller must hold mutex.
+    // On Windows, Open() uses _wstat() directly instead of calling this.
     bool is_modified() {
         time_t mtime = st.st_mtime;
-        stat(filepath.c_str(), &st);
+        ::stat(filepath.c_str(), &st);
         return mtime != st.st_mtime;
     }
 
+    // NOTE: caller must hold mutex
     bool is_complete() {
-        if(S_ISDIR(st.st_mode)) return filebuf.len > 0;
-        return filebuf.len == st.st_size;
+        if (S_ISDIR(st.st_mode)) return filebuf.len > 0;
+        return filebuf.len == (size_t)st.st_size;
     }
 
-    void resize_buf(int filesize) {
-        buf.resize(HTTP_HEADER_MAX_LENGTH + filesize);
-        filebuf.base = buf.base + HTTP_HEADER_MAX_LENGTH;
+    // NOTE: caller must hold mutex — invalidates filebuf/httpbuf pointers
+    void resize_buf(size_t filesize, int reserved) {
+        if (reserved < 0) reserved = 0;
+        header_reserve = reserved;
+        buf.resize((size_t)reserved + filesize);
+        filebuf.base = buf.base + reserved;
         filebuf.len = filesize;
+        // Invalidate httpbuf since buffer may have been reallocated
+        httpbuf.base = NULL;
+        httpbuf.len = 0;
+        header_used = 0;
     }
 
-    void prepend_header(const char* header, int len) {
-        if (len > HTTP_HEADER_MAX_LENGTH) return;
+    void resize_buf(size_t filesize) {
+        resize_buf(filesize, header_reserve);
+    }
+
+    // Thread-safe: prepend header into reserved space.
+    // Returns true on success, false if header exceeds reserved space.
+    // On failure, httpbuf falls back to filebuf (body only, no header).
+    bool prepend_header(const char* header, int len) {
+        std::lock_guard<std::mutex> lock(mutex);
+        if (len <= 0 || len > header_reserve) {
+            // Safe fallback: point httpbuf at filebuf so callers always get valid data
+            httpbuf = filebuf;
+            header_used = 0;
+            return false;
+        }
         httpbuf.base = filebuf.base - len;
-        httpbuf.len = len + filebuf.len;
+        httpbuf.len = (size_t)len + filebuf.len;
         memcpy(httpbuf.base, header, len);
+        header_used = len;
+        return true;
     }
+
+    // --- thread-safe accessors ---
+    int  get_header_reserve()  const { std::lock_guard<std::mutex> lock(mutex); return header_reserve; }
+    int  get_header_used()     const { std::lock_guard<std::mutex> lock(mutex); return header_used; }
+    int  get_header_remaining() const { std::lock_guard<std::mutex> lock(mutex); return header_reserve - header_used; }
+    bool header_fits(int len)  const { std::lock_guard<std::mutex> lock(mutex); return len > 0 && len <= header_reserve; }
 } file_cache_t;
 
-typedef std::shared_ptr<file_cache_t>           file_cache_ptr;
+typedef std::shared_ptr<file_cache_t> file_cache_ptr;
 
-class FileCache : public hv::LRUCache<std::string, file_cache_ptr> {
+class HV_EXPORT FileCache : public hv::LRUCache<std::string, file_cache_ptr> {
 public:
-    int             stat_interval;
-    int             expired_time;
+    // --- configurable parameters (were hardcoded macros before) ---
+    int stat_interval;      // seconds between stat() checks
+    int expired_time;       // seconds before cache entry expires
+    int max_header_length;  // reserved header bytes per entry
+    int max_file_size;      // max cached file size (larger = large-file path)
 
-    FileCache(size_t capacity = FILE_CACHE_MAX_NUM);
+    explicit FileCache(size_t capacity = FILE_CACHE_DEFAULT_MAX_NUM);
 
     struct OpenParam {
-        bool need_read;
-        int  max_read;
-        const char* path;
-        size_t  filesize;
-        int  error;
+        bool    need_read;
+        int     max_read;       // per-request override for max file size
+        const char* path;       // URL path (for directory listing)
+        size_t  filesize;       // [out] actual file size
+        int     error;          // [out] error code if Open returns NULL
 
         OpenParam() {
             need_read = true;
-            max_read = FILE_CACHE_MAX_SIZE;
+            max_read = FILE_CACHE_DEFAULT_MAX_FILE_SIZE;
             path = "/";
             filesize = 0;
             error = 0;
         }
     };
+
     file_cache_ptr Open(const char* filepath, OpenParam* param);
     bool Exists(const char* filepath) const;
     bool Close(const char* filepath);
     void RemoveExpiredFileCache();
 
+    // --- new: getters ---
+    int  GetMaxHeaderLength()   const { return max_header_length; }
+    int  GetMaxFileSize()       const { return max_file_size; }
+    int  GetStatInterval()      const { return stat_interval; }
+    int  GetExpiredTime()       const { return expired_time; }
+
+    // --- new: setters ---
+    void SetMaxHeaderLength(int len)    { max_header_length = len < 0 ? 0 : len; }
+    void SetMaxFileSize(int size)       { max_file_size = size < 1 ? 1 : size; }
+
 protected:
     file_cache_ptr Get(const char* filepath);
 };