{"id":208309,"date":"2025-07-08T08:39:39","date_gmt":"2025-07-08T00:39:39","guid":{"rendered":"https:\/\/server.hk\/cnblog\/208309\/"},"modified":"2025-07-08T08:39:39","modified_gmt":"2025-07-08T00:39:39","slug":"%e5%a6%82%e4%bd%95%e5%ae%9e%e7%8e%b0go%e5%b9%b6%e5%8f%91map%e6%88%96slice%e6%9d%a5%e6%9b%b4%e5%bf%ab%e5%9c%b0%e7%ae%a1%e7%90%86%e6%ad%a3%e5%9c%a8%e4%bd%bf%e7%94%a8%e7%9a%84%e8%b5%84%e6%ba%90%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/208309\/","title":{"rendered":"\u5982\u4f55\u5b9e\u73b0Go\u5e76\u53d1map\u6216slice\u6765\u66f4\u5feb\u5730\u7ba1\u7406\u6b63\u5728\u4f7f\u7528\u7684\u8d44\u6e90\uff1f"},"content":{"rendered":"<p><b><\/b> <\/p>\n<p>\u5f53\u524d\u4f4d\u7f6e\uff1a <span>&gt;<\/span> <span>&gt;<\/span> <span>&gt;<\/span> <span>&gt;<\/span> <span>\u5982\u4f55\u5b9e\u73b0Go\u5e76\u53d1map\u6216slice\u6765\u66f4\u5feb\u5730\u7ba1\u7406\u6b63\u5728\u4f7f\u7528\u7684\u8d44\u6e90\uff1f<\/span><\/p>\n<p><span>\u6765\u6e90\uff1astackoverflow<\/span><br \/>\n<span>2024-05-01 16:03:33<\/span><br \/>\n<span><i><\/i>0\u6d4f\u89c8<\/span><br \/>\n<span style=\"cursor: pointer\"><i><\/i>\u6536\u85cf<\/span> <\/p>\n<p>\u6765\u5230\u7684\u5927\u5bb6\uff0c\u76f8\u4fe1\u90fd\u662f\u7f16\u7a0b\u5b66\u4e60\u7231\u597d\u8005\uff0c\u5e0c\u671b\u5728\u8fd9\u91cc\u5b66\u4e60Golang\u76f8\u5173\u7f16\u7a0b\u77e5\u8bc6\u3002\u4e0b\u9762\u672c\u7bc7\u6587\u7ae0\u5c31\u6765\u5e26\u5927\u5bb6\u804a\u804a\u300a\u5982\u4f55\u5b9e\u73b0Go\u5e76\u53d1map\u6216slice\u6765\u66f4\u5feb\u5730\u7ba1\u7406\u6b63\u5728\u4f7f\u7528\u7684\u8d44\u6e90\uff1f\u300b\uff0c\u4ecb\u7ecd\u4e00\u4e0b\uff0c\u5e0c\u671b\u5bf9\u5927\u5bb6\u7684\u77e5\u8bc6\u79ef\u7d2f\u6709\u6240\u5e2e\u52a9\uff0c\u52a9\u529b\u5b9e\u6218\u5f00\u53d1\uff01<\/p>\n<p> \u95ee\u9898\u5185\u5bb9<br \/>\n <\/p>\n<p>\u60f3\u8c61\u4e00\u4e0b\uff0c\u4f60\u6709\u4e00\u4e2a\u7ed3\u6784\u4f53\uff0c\u4ee3\u8868\u4e00\u6b21\u53ea\u6709\u4e00\u4e2a\u7528\u6237\u53ef\u4ee5\u8bbf\u95ee\u7684\u8d44\u6e90\u3002\u53ef\u80fd\u770b\u8d77\u6765\u50cf\u8fd9\u6837\uff1a<\/p>\n<pre>type resource struct{\n    inuse bool\/\/or int32\/int64 is you want to use atomics\n    resource string \/\/parameters that map to the resource, think `\/dev\/chardevicexxx`\n}\n<\/pre>\n<p>\u8fd9\u4e9b\u8d44\u6e90\u7684\u6570\u91cf\u662f\u6709\u9650\u7684\uff0c\u7528\u6237\u5c06\u968f\u673a\u4e14\u5e76\u53d1\u5730\u8bf7\u6c42\u8bbf\u95ee\u5b83\u4eec\uff0c\u56e0\u6b64\u60a8\u5c06\u5b83\u4eec\u6253\u5305\u5728\u7ba1\u7406\u5668\u4e2d<\/p>\n<pre>type resourcemanager struct{\n    resources []*resource \/\/or a map \n}\n<\/pre>\n<p>\u6211\u6b63\u5728\u5c1d\u8bd5\u627e\u51fa\u7ba1\u7406\u5668\u521b\u5efa\u51fd\u6570 <code>func (m *resourcemanager)getunusedresouce()(*resouce,error)<\/code> \u7684\u6700\u4f73\u3001\u5b89\u5168\u65b9\u6cd5\uff0c\u8be5\u51fd\u6570\u5c06\uff1a<\/p>\n<ul>\n<li>\u8fed\u4ee3\u6240\u6709\u8d44\u6e90\uff0c\u76f4\u5230\u627e\u5230\u672a\u4f7f\u7528\u7684\u8d44\u6e90<\/li>\n<li>\u5c06\u5176\u6807\u8bb0\u4e3a inuse \u5e76\u5c06 *resouce \u8fd4\u56de\u5230\u8c03\u7528\u4e0a\u4e0b\u6587\/goroutine<\/li>\n<li>\u6211\u4f1a\u9501\u5b9a\u4ee5\u907f\u514d\u4efb\u4f55\u7cfb\u7edf\u7ea7\u9501\u5b9a\uff08flock\uff09\uff0c\u5e76\u5728 go \u4e2d\u5b8c\u6210\u8fd9\u4e00\u5207<\/li>\n<li>\u8fd8\u9700\u8981\u6709\u4e00\u4e2a\u51fd\u6570\u6765\u6807\u8bb0\u8d44\u6e90\u4e0d\u518d\u4f7f\u7528<\/li>\n<\/ul>\n<p>\u73b0\u5728\uff0c\u5f53\u6211\u8fed\u4ee3\u6574\u4e2a\u5207\u7247\u65f6\uff0c\u6211\u5728\u7ba1\u7406\u5668\u4e2d\u4f7f\u7528\u4e92\u65a5\u9501\u6765\u9501\u5b9a\u8bbf\u95ee\u3002\u5b83\u662f\u5b89\u5168\u7684\uff0c\u4f46\u6211\u5e0c\u671b\u901a\u8fc7\u80fd\u591f\u540c\u65f6\u641c\u7d22\u5df2\u4f7f\u7528\u7684\u8d44\u6e90\u5e76\u5904\u7406\u4e24\u4e2a\u8bd5\u56fe\u5c06\u540c\u4e00\u8d44\u6e90\u6807\u8bb0\u4e3a inuse \u7684 goroutine \u6765\u52a0\u5feb\u901f\u5ea6\u3002<\/p>\n<h3>\u66f4\u65b0<\/h3>\n<p>\u6211\u7279\u522b\u60f3\u77e5\u9053\u662f\u5426\u5c06\u8d44\u6e90 <code>inuse<\/code> \u5b57\u6bb5\u8bbe\u7f6e\u4e3a <code>int64<\/code> \u7136\u540e\u4f7f\u7528 <code>atomic.compareandswapint64<\/code> \u5c06\u5141\u8bb8\u8d44\u6e90\u7ba1\u7406\u5668\u5728\u53d1\u73b0\u672a\u4f7f\u7528\u7684\u8d44\u6e90\u65f6\u6b63\u786e\u9501\u5b9a\uff1a<\/p>\n<pre>func (m *ResourceManager)GetUnusedResouce()(*Resouce,error){\n    for i := range Resources{\n        if atomic.CompareAndSwapInt64(&amp;Resouces[i].InUse,1){\n            return Resouces[i],nil\n        }\n    }\n    return nil, errors.New(\"all resouces in use\")\n}\n<\/pre>\n<p>\u4efb\u4f55\u53ef\u4ee5\u66f4\u597d\u5730\u6d4b\u8bd5\u8fd9\u4e00\u70b9\u7684\u5355\u5143\u6d4b\u8bd5\u4e5f\u5c06\u4e0d\u80dc\u611f\u6fc0\u3002<\/p>\n<p> <\/p>\n<h2>\u6b63\u786e\u7b54\u6848<\/h2>\n<p> <\/p>\n<p>\u95ee\u9898\u4e2d\u7684 <code>getunusedresouce<\/code> \u51fd\u6570\u53ef\u80fd\u4f1a\u5bf9\u6240\u6709\u8d44\u6e90\u6267\u884c\u6bd4\u8f83\u548c\u4ea4\u6362\u64cd\u4f5c\u3002\u6839\u636e\u8d44\u6e90\u6570\u91cf\u548c\u5e94\u7528\u7a0b\u5e8f\u8bbf\u95ee\u6a21\u5f0f\uff0c\u6267\u884c\u53d7\u4e92\u65a5\u9501\u4fdd\u62a4\u7684\u5c11\u91cf\u64cd\u4f5c\u53ef\u80fd\u4f1a\u66f4\u5feb\u3002<\/p>\n<p>\u4f7f\u7528\u5355\u94fe\u8868\u5b9e\u73b0\u5feb\u901f\u7684get\u548cput\u64cd\u4f5c\u3002<\/p>\n<pre>type resource struct {\n    next     *resource\n    resource string\n}\n\ntype resourcemanager struct {\n    free *resource\n    mu   sync.mutex\n}\n\n\/\/ get gets a free resource from the manager or returns\n\/\/ nil when the manager is empty.\nfunc (m *resourcemanager) get() *resource {\n    m.mu.lock()\n    defer m.mu.unlock()\n    result := m.free\n    if m.free != nil {\n        m.free = m.free.next\n    }\n    return result\n}\n\n\/\/ put returns a resource to the pool.\nfunc (m *resourcemanager) put(r *resource) {\n    m.mu.lock()\n    defer m.mu.unlock()\n    r.next = m.free\n    m.free = r\n}<\/pre>\n<p>\u4ee5\u4e0b\u662f\u6d4b\u8bd5\u4e2d\u7684\u4f7f\u7528\u793a\u4f8b\uff1a<\/p>\n<pre>func testresourcemanager(t *testing.t) {\n\n    \/\/ add free resources to a manager.\n    var m resourcemanager\n    m.put(&amp;resource{resource: \"\/dev\/a\"})\n    m.put(&amp;resource{resource: \"\/dev\/b\"})\n\n    \/\/ test that we can get all resources from the pool.\n\n    ra := m.get()\n    rb := m.get()\n    if ra.resource &gt; rb.resource {\n        \/\/ sort ra, rb to make test independent of order.\n        ra, rb = rb, ra\n    }\n    if ra == nil || ra.resource != \"\/dev\/a\" {\n        t.errorf(\"ra is %v, want \/dev\/a\", ra)\n    }\n    if rb == nil || rb.resource != \"\/dev\/b\" {\n        t.errorf(\"rb is %v, want \/dev\/b\", rb)\n    }\n\n    \/\/ check for empty pool.\n\n    r := m.get()\n    if r != nil {\n        t.errorf(\"r is %v, want nil\", r)\n    }\n\n    \/\/ return one resource and try again.\n\n    m.put(ra)\n    ra = m.get()\n    if ra == nil || ra.resource != \"\/dev\/a\" {\n        t.errorf(\"ra is %v, want \/dev\/a\", ra)\n    }\n    r = m.get()\n    if r != nil {\n        t.errorf(\"r is %v, want nil\", r)\n    }\n\n}<\/pre>\n<p>\u3002<\/p>\n<p>\u5982\u679c\u8d44\u6e90\u6570\u91cf\u5b58\u5728\u5df2\u77e5\u7684\u5408\u7406\u9650\u5236\uff0c\u8bf7\u4f7f\u7528\u901a\u9053\u3002\u6b64\u65b9\u6cd5\u5229\u7528\u4e86\u8fd0\u884c\u65f6\u9ad8\u5ea6\u4f18\u5316\u7684\u901a\u9053\u5b9e\u73b0\u3002<\/p>\n<pre>type resource struct {\n    resource string\n}\n\ntype resourcemanager struct {\n    free chan *resource\n}\n\n\/\/ get gets a free resource from the manager or returns\n\/\/ nil when the manager is empty.\nfunc (m *resourcemanager) get() *resource {\n    select {\n    case r := &lt;-m.free:\n        return r\n    default:\n        return nil\n    }\n}\n\n\/\/ put returns a resource to the pool.\nfunc (m *resourcemanager) put(r *resource) {\n    m.free &lt;- r\n}\n\n\/\/ newresourcemanager returns a manager that can hold up to\n\/\/ n free resources.\nfunc newresourcemanager(n int) *resourcemanager {\n    return &amp;resourcemanager{free: make(chan *resource, n)}\n}<\/pre>\n<p>\u4f7f\u7528\u4e0a\u9762\u7684 <code>testresourcemanager<\/code> \u51fd\u6570\u6d4b\u8bd5\u6b64\u5b9e\u73b0\uff0c\u4f46\u5c06 <code>var m resourcemanager<\/code> \u66ff\u6362\u4e3a <code>m := newresourcemanager(4)<\/code>\u3002<\/p>\n<p>\u3002<\/p>\n<p>\u7ed9\u5b9a\u8d44\u6e90\u662f\u5426\u6b63\u5728\u4f7f\u7528\u4e0d\u662f <code>resource<\/code> \u672c\u8eab\u7684\u5c5e\u6027\uff0c\u800c\u662f <code>resourcemanager<\/code> \u7684\u5c5e\u6027\u3002<\/p>\n<p>\u4e8b\u5b9e\u4e0a\uff0c\u6ca1\u6709\u5fc5\u8981\u8ddf\u8e2a\u6b63\u5728\u4f7f\u7528\u7684\u8d44\u6e90\uff08\u9664\u975e\u7531\u4e8e\u95ee\u9898\u4e2d\u672a\u63d0\u53ca\u7684\u67d0\u79cd\u539f\u56e0\u9700\u8981\u8ddf\u8e2a\uff09\u3002\u6b63\u5728\u4f7f\u7528\u7684\u8d44\u6e90\u5728\u91ca\u653e\u65f6\u53ef\u4ee5\u7b80\u5355\u5730\u653e\u56de\u6c60\u4e2d\u3002<\/p>\n<p>\u8fd9\u662f\u4f7f\u7528\u901a\u9053\u7684\u53ef\u80fd\u5b9e\u73b0\u3002\u4e0d\u9700\u8981\u4e00\u4e2a\u4e92\u65a5\u9501\uff0c\u4e5f\u4e0d\u9700\u8981\u4efb\u4f55\u539f\u5b50 cas\u3002<\/p>\n<pre>package main\n\nimport (\n    fmt \"fmt\"\n    \"time\"\n)\n\ntype Resource struct {\n    Data string\n}\n\ntype ResourceManager struct {\n    resources []*Resource\n    closeCh   chan struct{}\n    acquireCh chan *Resource\n    releaseCh chan *Resource\n}\n\nfunc NewResourceManager() *ResourceManager {\n    r := &amp;ResourceManager{\n        closeCh:   make(chan struct{}),\n        acquireCh: make(chan *Resource),\n        releaseCh: make(chan *Resource),\n    }\n    go r.run()\n    return r\n}\n\nfunc (r *ResourceManager) run() {\n    defer close(r.acquireCh)\n    for {\n        if len(r.resources) &gt; 0 {\n            select {\n            case r.acquireCh &lt;- r.resources[len(r.resources)-1]:\n                r.resources = r.resources[:len(r.resources)-1]\n            case res := &lt;-r.releaseCh:\n                r.resources = append(r.resources, res)\n            case &lt;-r.closeCh:\n                return\n            }\n        } else {\n            select {\n            case res := &lt;-r.releaseCh:\n                r.resources = append(r.resources, res)\n            case &lt;-r.closeCh:\n                return\n            }\n        }\n    }\n}\n\nfunc (r *ResourceManager) AcquireResource() *Resource {\n    return &lt;-r.acquireCh\n}\n\nfunc (r *ResourceManager) ReleaseResource(res *Resource) {\n    r.releaseCh &lt;- res\n}\n\nfunc (r *ResourceManager) Close() {\n    close(r.closeCh)\n}\n\n\/\/ small demo below ...\n\nfunc test(id int, r *ResourceManager) {\n    for {\n        res := r.AcquireResource()\n        fmt.Printf(\"test %d: %s\\n\", id, res.Data)\n        time.Sleep(time.Millisecond)\n        r.ReleaseResource(res)\n    }\n}\n\nfunc main() {\n    r := NewResourceManager()\n    r.ReleaseResource(&amp;Resource{\"Resource A\"}) \/\/ initial setup\n    r.ReleaseResource(&amp;Resource{\"Resource B\"}) \/\/ initial setup\n    go test(1, r)\n    go test(2, r)\n    go test(3, r) \/\/ 3 consumers, but only 2 resources ...\n    time.Sleep(time.Second)\n    r.Close()\n}<\/pre>\n<p>\u7406\u8bba\u8981\u638c\u63e1\uff0c\u5b9e\u64cd\u4e0d\u80fd\u843d\uff01\u4ee5\u4e0a\u5173\u4e8e\u300a\u5982\u4f55\u5b9e\u73b0Go\u5e76\u53d1map\u6216slice\u6765\u66f4\u5feb\u5730\u7ba1\u7406\u6b63\u5728\u4f7f\u7528\u7684\u8d44\u6e90\uff1f\u300b\u7684\u8be6\u7ec6\u4ecb\u7ecd\uff0c\u5927\u5bb6\u90fd\u638c\u63e1\u4e86\u5427\uff01\u5982\u679c\u60f3\u8981\u7ee7\u7eed\u63d0\u5347\u81ea\u5df1\u7684\u80fd\u529b\uff0c\u90a3\u4e48\u5c31\u6765\u5173\u6ce8\u516c\u4f17\u53f7\u5427\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5f53\u524d\u4f4d\u7f6e\uff1a &gt; &gt; &#46;&#46;&#46;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4925],"tags":[],"class_list":["post-208309","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/208309","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=208309"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/208309\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=208309"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=208309"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=208309"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}