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Diffstat (limited to '')
-rw-r--r-- | dependencies/pkg/mod/go.uber.org/zap@v1.23.0/stacktrace.go | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/dependencies/pkg/mod/go.uber.org/zap@v1.23.0/stacktrace.go b/dependencies/pkg/mod/go.uber.org/zap@v1.23.0/stacktrace.go new file mode 100644 index 0000000..3d187fa --- /dev/null +++ b/dependencies/pkg/mod/go.uber.org/zap@v1.23.0/stacktrace.go @@ -0,0 +1,176 @@ +// Copyright (c) 2016 Uber Technologies, Inc. +// +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: +// +// The above copyright notice and this permission notice shall be included in +// all copies or substantial portions of the Software. +// +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +// THE SOFTWARE. + +package zap + +import ( + "runtime" + "sync" + + "go.uber.org/zap/buffer" + "go.uber.org/zap/internal/bufferpool" +) + +var _stacktracePool = sync.Pool{ + New: func() interface{} { + return &stacktrace{ + storage: make([]uintptr, 64), + } + }, +} + +type stacktrace struct { + pcs []uintptr // program counters; always a subslice of storage + frames *runtime.Frames + + // The size of pcs varies depending on requirements: + // it will be one if the only the first frame was requested, + // and otherwise it will reflect the depth of the call stack. + // + // storage decouples the slice we need (pcs) from the slice we pool. + // We will always allocate a reasonably large storage, but we'll use + // only as much of it as we need. + storage []uintptr +} + +// stacktraceDepth specifies how deep of a stack trace should be captured. +type stacktraceDepth int + +const ( + // stacktraceFirst captures only the first frame. + stacktraceFirst stacktraceDepth = iota + + // stacktraceFull captures the entire call stack, allocating more + // storage for it if needed. + stacktraceFull +) + +// captureStacktrace captures a stack trace of the specified depth, skipping +// the provided number of frames. skip=0 identifies the caller of +// captureStacktrace. +// +// The caller must call Free on the returned stacktrace after using it. +func captureStacktrace(skip int, depth stacktraceDepth) *stacktrace { + stack := _stacktracePool.Get().(*stacktrace) + + switch depth { + case stacktraceFirst: + stack.pcs = stack.storage[:1] + case stacktraceFull: + stack.pcs = stack.storage + } + + // Unlike other "skip"-based APIs, skip=0 identifies runtime.Callers + // itself. +2 to skip captureStacktrace and runtime.Callers. + numFrames := runtime.Callers( + skip+2, + stack.pcs, + ) + + // runtime.Callers truncates the recorded stacktrace if there is no + // room in the provided slice. For the full stack trace, keep expanding + // storage until there are fewer frames than there is room. + if depth == stacktraceFull { + pcs := stack.pcs + for numFrames == len(pcs) { + pcs = make([]uintptr, len(pcs)*2) + numFrames = runtime.Callers(skip+2, pcs) + } + + // Discard old storage instead of returning it to the pool. + // This will adjust the pool size over time if stack traces are + // consistently very deep. + stack.storage = pcs + stack.pcs = pcs[:numFrames] + } else { + stack.pcs = stack.pcs[:numFrames] + } + + stack.frames = runtime.CallersFrames(stack.pcs) + return stack +} + +// Free releases resources associated with this stacktrace +// and returns it back to the pool. +func (st *stacktrace) Free() { + st.frames = nil + st.pcs = nil + _stacktracePool.Put(st) +} + +// Count reports the total number of frames in this stacktrace. +// Count DOES NOT change as Next is called. +func (st *stacktrace) Count() int { + return len(st.pcs) +} + +// Next returns the next frame in the stack trace, +// and a boolean indicating whether there are more after it. +func (st *stacktrace) Next() (_ runtime.Frame, more bool) { + return st.frames.Next() +} + +func takeStacktrace(skip int) string { + stack := captureStacktrace(skip+1, stacktraceFull) + defer stack.Free() + + buffer := bufferpool.Get() + defer buffer.Free() + + stackfmt := newStackFormatter(buffer) + stackfmt.FormatStack(stack) + return buffer.String() +} + +// stackFormatter formats a stack trace into a readable string representation. +type stackFormatter struct { + b *buffer.Buffer + nonEmpty bool // whehther we've written at least one frame already +} + +// newStackFormatter builds a new stackFormatter. +func newStackFormatter(b *buffer.Buffer) stackFormatter { + return stackFormatter{b: b} +} + +// FormatStack formats all remaining frames in the provided stacktrace -- minus +// the final runtime.main/runtime.goexit frame. +func (sf *stackFormatter) FormatStack(stack *stacktrace) { + // Note: On the last iteration, frames.Next() returns false, with a valid + // frame, but we ignore this frame. The last frame is a a runtime frame which + // adds noise, since it's only either runtime.main or runtime.goexit. + for frame, more := stack.Next(); more; frame, more = stack.Next() { + sf.FormatFrame(frame) + } +} + +// FormatFrame formats the given frame. +func (sf *stackFormatter) FormatFrame(frame runtime.Frame) { + if sf.nonEmpty { + sf.b.AppendByte('\n') + } + sf.nonEmpty = true + sf.b.AppendString(frame.Function) + sf.b.AppendByte('\n') + sf.b.AppendByte('\t') + sf.b.AppendString(frame.File) + sf.b.AppendByte(':') + sf.b.AppendInt(int64(frame.Line)) +} |